| V-ID | CCI | CAT | Title | Description | Check Procedures | Fixtext |
| V-756 | CCI-000213 | medium | The system must require authentication upon booting into single-user and maintenance modes. | If the system does not require valid root authentication before it boots into single-user or maintenance mode, anyone who invokes single-user or maintenance mode is granted privileged access to all files on the system. | Check if the system requires a password for entering single-user mode. # grep ':S:' /etc/inittab If /sbin/sulogin is not listed, this is a finding. | Edit /etc/inittab and set sulogin to run in single-user mode. Example line in /etc/inittab: ~:S:wait:/sbin/sulogin |
| V-761 | CCI-000764 | medium | All accounts on the system must have unique user or account names. | A unique user name is the first part of the identification and authentication process. If user names are not unique, there can be no accountability on the system for auditing purposes. Multiple accounts sharing the same name could result in the denial of service to one or both of the accounts or unauthorized access to files or privileges. | Check the system for duplicate account names. Example: # pwck -r If any duplicate account names are found, this is a finding. | Change user account names, or delete accounts, so each account has a unique name. |
| V-763 | CCI-000048 | medium | The Department of Defense (DoD) login banner must be displayed immediately prior to, or as part of, console login prompts. | Failure to display the logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources. | Access the system console and make a login attempt. Check for either of the following login banners based on the character limitations imposed by the system. An exact match is required. If one of these banners is not displayed, this is a finding. You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests- -not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. OR I've read & consent to terms in IS user agreem't. | Edit /etc/issue and add one of the DoD login banners (based on the character limitations imposed by the system). DoD Login Banners: You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests- -not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. OR I've read & consent to terms in IS user agreem't. |
| V-765 | CCI-000126 | medium | Successful and unsuccessful logins and logouts must be logged. | Monitoring and recording successful and unsuccessful logins assists in tracking unauthorized access to the system. Without this logging, the ability to track unauthorized activity to specific user accounts may be diminished. | Determine if all logon attempts are being logged. Procedure: Verify successful logins are being logged: # last -R | more If the command does not return successful logins, this is a finding. Verify if unsuccessful logons are being logged: # lastb -R | more If the command does not return unsuccessful logins, this is a finding. | Make sure the collection files exist. Procedure: If there are no successful logins being returned from the "last" command, create /var/log/wtmp: # touch /var/log/wtmp If there are no unsuccessful logins being returned from the "lastb" command, create /var/log/btmp: # touch /var/log/btmp |
| V-769 | CCI-000225 | medium | The root user must not own the logon session for an application requiring a continuous display. | If an application is providing a continuous display and is running with root privileges, unauthorized users could interrupt the process and gain root access to the system. | If there is an application running on the system continuously in use (such as a network monitoring application), ask the SA what the name of the application is. Verify documentation exists for the requirement and justification of the application. If no documentation exists, this is a finding. Execute "ps -ef | more" to determine which user owns the process(es) associated with the application. If the owner is root, this is a finding. | Configure the system so the owner of a session requires a continuous screen display, such as a network management display, is not root. Ensure the display is also located in a secure, controlled access area. Document and justify this requirement and ensure the terminal and keyboard for the display (or workstation) are secure from all but authorized personnel by maintaining them in a secure area, in a locked cabinet where a swipe card, or other positive forms of identification, must be used to gain entry. |
| V-770 | CCI-000366 | high | The system must not have accounts configured with blank or null passwords. | If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. If the root user is configured without a password, the entire system may be compromised. For user accounts not using password authentication, the account must be configured with a password lock value instead of a blank or null value. | Verify the system will not log in accounts with blank passwords. # grep nullok /etc/pam.d/system-auth /etc/pam.d/system-auth-ac If an entry for nullok is found, this is a finding on Linux. | Edit /etc/pam.d/system-auth and remove the "nullok" setting. |
| V-773 | CCI-000366 | medium | The root account must be the only account having a UID of 0. | If an account has a UID of 0, it has root authority. Multiple accounts with a UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account. | Check the system for duplicate UID 0 assignments by listing all accounts assigned UID 0. Procedure: # cat /etc/passwd | awk -F":" '{print$1":"$3":"}' | grep ":0:" If any accounts other than root are assigned UID 0, this is a finding. | Remove or change the UID of accounts other than root that have UID 0. |
| V-774 | CCI-000366 | low | The root user's home directory must not be the root directory (/). | Changing the root home directory to something other than / and assigning it a 0700 protection makes it more difficult for intruders to manipulate the system by reading the files root places in its default directory. It also gives root the same discretionary access control for root's home directory as for the other user home directories. | Determine if root is assigned a home directory other than / by listing its home directory. Procedure: # grep "^root" /etc/passwd | awk -F":" '{print $6}' If the root user home directory is /, this is a finding. | The root home directory should be something other than / (such as /roothome). Procedure: # mkdir /rootdir # chown root /rootdir # chgrp root /rootdir # chmod 700 /rootdir # cp -r /.??* /rootdir/. Then, edit the passwd file and change the root home directory to /rootdir. The cp -r /.??* command copies all files and subdirectories of file names beginning with "." into the new root directory, which preserves the previous root environment. Ensure you are in the "/" directory when executing the "cp" command. |
| V-775 | CCI-000225 | medium | The root account's home directory (other than /) must have mode 0700. | Permissions greater than 0700 could allow unauthorized users access to the root home directory. | Check the mode of the root home directory. Procedure: # grep "^root" /etc/passwd | awk -F":" '{print $6}' # ls -ld <root home directory> If the mode of the directory is not equal to 0700, this is a finding. If the home directory is /, this check will be marked "Not Applicable". | The root home directory will have permissions of 0700. Do not change the protections of the / directory. Use the following command to change protections for the root home directory: # chmod 0700 /rootdir. |
| V-776 | CCI-000366 | medium | The root account's executable search path must be the vendor default and must contain only absolute paths. | The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon or two consecutive colons, this is interpreted as the current working directory. Entries starting with a slash (/) are absolute paths. | To view the root user's PATH, log in as the root user, and execute: # env | grep PATH This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry starts with a character other than a slash (/), this is a finding. If directories beyond those in the vendor's default root path are present. This is a finding. | Edit the root user's local initialization files ~/.profile,~/.bashrc (assuming root shell is bash). Change any found PATH variable settings to the vendor's default path for the root user. Remove any empty path entries or references to relative paths. |
| V-777 | CCI-000366 | medium | The root account must not have world-writable directories in its executable search path. | If the root search path contains a world-writable directory, malicious software could be placed in the path by intruders and/or malicious users and inadvertently run by root with all of root's privileges. | Check for world-writable permissions on all directories in the root user's executable search path. Procedure: # ls -ld `echo $PATH | sed "s/:/ /g"` If any of the directories in the PATH variable are world-writable, this is a finding. | For each world-writable path in root's executable search path, do one of the following: 1. Remove the world-writable permission on the directory. Procedure: # chmod o-w <path> 2. Remove the world-writable directory from the executable search path. Procedure: Identify and edit the initialization file referencing the world-writable directory and remove it from the PATH variable. |
| V-780 | CCI-000366 | medium | GIDs reserved for system accounts must not be assigned to non-system groups. | Reserved GIDs are typically used by system software packages. If non-system groups have GIDs in this range, they may conflict with system software, possibly leading to the group having permissions to modify system files. | Confirm all accounts with a GID of 499 and below are used by a system account. Procedure: List all the users with a GID of 0-499. # cut -d: -f 1,4 /etc/passwd|egrep ":[1-4][0-9]{2}$|:[0-9]{1,2}$" If a GID reserved for system accounts (0 - 499) is used by a non-system account, this is a finding. | Change the primary group GID numbers for non-system accounts with reserved primary group GIDs (those less or equal to 499). |
| V-781 | CCI-000366 | low | All GIDs referenced in the /etc/passwd file must be defined in the /etc/group file. | If a user is assigned the GID of a group not existing on the system, and a group with the GID is subsequently created, the user may have unintended rights to the group. | Perform the following to ensure there are no GIDs referenced in /etc/passwd not defined in /etc/group: # pwck -r If GIDs referenced in /etc/passwd are not defined in /etc/group are returned, this is a finding. | Add a group to the system for each GID referenced without a corresponding group. |
| V-782 | CCI-001259 | medium | The system must have a host-based intrusion detection tool installed. | Without a host-based intrusion detection tool, there is no system-level defense when an intruder gains access to a system or network. Additionally, a host-based intrusion detection tool can provide methods to immediately lock out detected intrusion attempts. | Ask the SA or IAO if a host-based intrusion detection application is loaded on the system. The preferred intrusion detection system is McAfee HBSS available through Cybercom. Procedure: Examine the system to see if the Host Intrusion Prevention System (HIPS) is installed #rpm -qa | grep MFEhiplsm If the MFEhiplsm package is installed, HBSS is being used on the system. If another host-based intrusion detection system is loaded on the system # find / -name <daemon name> Where <daemon name> is the name of the primary application daemon to determine if the application is loaded on the system. Determine if the application is active on the system. Procedure: # ps -ef | grep <daemon name> If no host-based intrusion detection system is installed on the system, this is a finding. | Install a host-based intrusion detection tool. |
| V-783 | CCI-001227 | medium | Vendor-recommended software patches and updates, and system security patches and updates, must be installed and up-to-date. | Timely patching is critical for maintaining the operational availability, confidentiality, and integrity of information technology (IT) systems. However, failure to keep operating system and application software patched is a common mistake made by IT professionals. New patches are released daily, and it is often difficult for even experienced system administrators to keep abreast of all the new patches. When new weaknesses in an operating system exist, patches are usually made available by the vendor to resolve the problems. If the most recent recommended updates and security patches are not installed, unauthorized users may take advantage of weaknesses present in the unpatched software. The lack of prompt attention to patching could result in a system compromise. | Obtain the list of available package updates from Red Hat. Check the available package updates have been installed on the system. Use the "rpm" command to list the packages installed on the system. Example: # rpm -qa -last If updated packages are available and applicable to the system and have not been installed, this is a finding. One source for the list of Red Hat updates is available at https://access.redhat.com/security/updates/active/ | Install the patches or updated packages available from the vendor. |
| V-784 | CCI-000225 | medium | System files and directories must not have uneven access permissions. | Discretionary access control is undermined if users, other than a file owner, have greater access permissions to system files and directories than the owner. | Check system directories for uneven file permissions. Procedure: # ls -lL /etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin Uneven file permissions exist if the file owner has less permissions than the group or other user classes. If any of the files in the above listed directories contain uneven file permissions, this is a finding. | Change the mode of files with uneven permissions so owners do not have less permission than group or world users. |
| V-785 | CCI-000366 | medium | All files and directories must have a valid owner. | Un-owned files and directories may be unintentionally inherited if a user is assigned the same UID as the UID of the un-owned files. | Check the system for files with no assigned owner. Procedure: # find / -nouser If any files have no assigned owner, this is a finding. Caution should be used when centralized authorization is used because valid files may appear as unowned due to communication issues. | All directories and files (executable and data) will have an identifiable owner and group name. Either trace files to an authorized user, change the file's owner to root, or delete them. Determine the legitimate owner of the files and use the chown command to set the owner and group to the correct value. If the legitimate owner cannot be determined, change the owner to root (but make sure none of the changed files remain executable because they could be Trojan horses or other malicious code). Examine the files to determine their origin and the reason for their lack of an owner/group. |
| V-786 | CCI-000225 | medium | All network services daemon files must have mode 0755 or less permissive. | Restricting permission on daemons will protect them from unauthorized modification and possible system compromise. | Check the mode of network services daemons. # find /usr/sbin -type f -perm +022 -exec stat -c %a:%n {} \; This will return the octal permissions and name of all files that are group or world writable. If any network services daemon listed is world or group writable (either or both of the 2 lowest order digits contain a 2, 3 or 6), this is a finding. Note: Network daemons not residing in these directories (such as httpd or sshd) must also be checked for the correct permissions. | Change the mode of the network services daemon. # chmod go-w <path> |
| V-787 | CCI-001314 | medium | System log files must have mode 0640 or less permissive. | If the system log files are not protected, unauthorized users could change the logged data, eliminating its forensic value. | Check the mode of log files. Procedure: # ls -lL /var/log /var/log/syslog /var/adm With the exception of /var/log/wtmp, if any of the log files have modes more permissive than 0640, this is a finding. | Change the mode of the system log file(s) to 0640 or less permissive. Procedure: # chmod 0640 /path/to/system-log-file Note: Do not confuse system log files with audit logs. |
| V-788 | CCI-000225 | medium | All skeleton files (typically those in /etc/skel) must have mode 0644 or less permissive. | If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files. | Check skeleton files permissions. # ls -alL /etc/skel If a skeleton file has a mode more permissive than 0644, this is a finding. | Change the mode of skeleton files with incorrect mode: # chmod 0644 <skeleton file> |
| V-789 | CCI-000225 | medium | NIS/NIS+/yp files must be owned by root, sys, or bin. | NIS/NIS+/yp files are part of the system's identification and authentication processes and are critical to system security. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture. | Perform the following to check NIS file ownership: # ls -la /var/yp/*; If the file ownership is not root, sys, or bin, this is a finding. | Change the ownership of NIS/NIS+/yp files to root, sys or bin. Procedure (example): # chown root <filename> |
| V-790 | CCI-000225 | medium | NIS/NIS+/yp files must be group-owned by root, sys, or bin. | NIS/NIS+/yp files are part of the system's identification and authentication processes and are, therefore, critical to system security. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture. | Perform the following to check NIS file ownership: # ls -la /var/yp/* If the file group ownership is not root, sys, or bin, this is a finding. | Perform the following to change NIS file ownership. # chown root /var/yp/* |
| V-791 | CCI-000225 | medium | The NIS/NIS+/yp command files must have mode 0755 or less permissive. | NIS/NIS+/yp files are part of the system's identification and authentication processes and are critical to system security. Unauthorized modification of these files could compromise these processes and the system. | Perform the following to check NIS file premissions. # ls -la /var/yp/*; If the file's mode is more permissive than 0755, this is a finding. | Change the mode of NIS/NIS+/yp command files to 0755 or less permissive. Procedure (example): # chmod 0755 <filename> |
| V-792 | CCI-000225 | low | Manual page files must have mode 0644 or less permissive. | If manual pages are compromised, misleading information could be inserted, causing actions to compromise the system. | Check the mode of the manual page files. Procedure: # ls -lL /usr/share/man /usr/share/info /usr/share/infopage If any of the manual page files have a mode more permissive than 0644, this is a finding. | Change the mode of manual page files to 0644 or less permissive. Procedure (example): # chmod 0644 /path/to/manpage |
| V-793 | CCI-001499 | medium | Library files must have mode 0755 or less permissive. | Unauthorized access could destroy the integrity of the library files. | Check the mode of library files. Procedure: # DIRS="/usr/lib /lib";for DIR in $DIRS;do find $DIR -type f -perm +022 -exec stat -c %a:%n {} \;;done This will return the octal permissions and name of all group or world writable files. If any file listed is world or group writable (either or both of the 2 lowest order digits contain a 2, 3 or 6), this is a finding. | Change the mode of library files to 0755 or less permissive. Procedure (example): # chmod go-w </path/to/library-file> Note: Library files should have an extension of ".a" or a ".so" extension, possibly followed by a version number. |
| V-794 | CCI-001499 | medium | All system command files must have mode 0755 or less permissive. | Restricting permissions will protect system command files from unauthorized modification. System command files include files present in directories used by the operating system for storing default system executables and files present in directories included in the system's default executable search paths. | Check the permissions for files in /etc, /bin, /usr/bin, /usr/lbin, /usr/usb, /sbin, and /usr/sbin. Procedure: # DIRS="/etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin";for DIR in $DIRS;do find $DIR -type f -perm +022 -exec stat -c %a:%n {} \;;done This will return the octal permissions and name of all group or world writable files. If any file listed is world or group writable (either or both of the 2 lowest order digits contain a 2, 3 or 6), this is a finding. Note: Elevate to Severity Code I if any file listed is world-writable. | Change the mode for system command files to 0755 or less permissive taking into account necessary GIUD and SUID bits. Procedure: # chmod go-w <filename> |
| V-795 | CCI-001499 | medium | All system files, programs, and directories must be owned by a system account. | Restricting permissions will protect the files from unauthorized modification. | Check the ownership of system files, programs, and directories. Procedure: # ls -lLa /etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin If any of the system files, programs, or directories are not owned by a system account, this is a finding. | Change the owner of system files, programs, and directories to a system account. Procedure: # chown root /some/system/file (A different system user may be used in place of root.) |
| V-796 | CCI-001499 | medium | System files, programs, and directories must be group-owned by a system group. | Restricting permissions will protect the files from unauthorized modification. | Check the group-ownership of system files, programs, and directories. Procedure: # ls -lLa /etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin If any system file, program, or directory is not owned by a system group, this is a finding. | Change the group-owner of system files to a system group. Procedure: # chgrp root /path/to/system/file (System groups other than root may be used.) |
| V-797 | CCI-000225 | medium | The /etc/shadow (or equivalent) file must be owned by root. | The /etc/shadow file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture. | Check the ownership of the /etc/shadow file. # ls -lL /etc/shadow If the /etc/shadow file is not owned by root, this is a finding. | Change the ownership of the /etc/shadow (or equivalent) file. # chown root /etc/shadow |
| V-798 | CCI-000225 | medium | The /etc/passwd file must have mode 0644 or less permissive. | If the passwd file is writable by a group-owner or the world, the risk of passwd file compromise is increased. The passwd file contains the list of accounts on the system and associated information. | Check the mode of the /etc/passwd file. Procedure: # ls -lL /etc/passwd If /etc/passwd has a mode more permissive than 0644, this is a finding. | Change the mode of the passwd file to 0644. Procedure: # chmod 0644 /etc/passwd |
| V-800 | CCI-000225 | medium | The /etc/shadow (or equivalent) file must have mode 0400. | The /etc/shadow file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root. | Check the mode of the /etc/shadow file. # ls -lL /etc/shadow If the /etc/shadow file has a mode more permissive than 0400, this is a finding. | Change the mode of the /etc/shadow (or equivalent) file. # chmod 0400 /etc/shadow |
| V-801 | CCI-000368 | medium | The owner, group-owner, mode, ACL, and location of files with the setuid bit set must be documented using site-defined procedures. | All files with the setuid bit set will allow anyone running these files to be temporarily assigned the UID of the file. While many system files depend on these attributes for proper operation, security problems can result if setuid is assigned to programs allowing reading and writing of files, or shell escapes. Only default vendor-supplied executables should have the setuid bit set. | List all setuid files on the system. Procedure: # find / -perm -4000 -exec ls -l {} \; | more Note: Executing these commands may result in large listings of files; the output may be redirected to a file for easier analysis. Ask the SA or IAO if files with the setuid bit set have been documented. Documentation must include the owner, group-owner, mode, ACL, and location of the files. If any undocumented file has its setuid bit set, this is a finding. | Document the files with the suid bit set or unset the suid bit on the executable. |
| V-802 | CCI-000368 | medium | The owner, group-owner, mode, ACL and location of files with the setgid bit set must be documented using site-defined procedures. | All files with the setgid bit set will allow anyone running these files to be temporarily assigned the GID of the file. While many system files depend on these attributes for proper operation, security problems can result if setgid is assigned to programs allowing reading and writing of files, or shell escapes. | List all setgid files on the system. Procedure: # find / -perm -2000 -exec ls -l {} \; | more Note: Executing these commands may result in large listings of files; the output may be redirected to a file for easier analysis. Ask the SA or IAO if files with the setgid bit set have been documented. Documentation must include owner, group-owner, mode, ACL, and location. If any undocumented file has its setgid bit set, this is a finding. | Document the files with the sgid bit set or unset the sgid bit on the executable. |
| V-803 | CCI-000318 | medium | The system must be checked weekly for unauthorized setuid files as well as unauthorized modification to authorized setuid files. | Files with the setuid bit set will allow anyone running these files to be temporarily assigned the UID of the file. While many system files depend on these attributes for proper operation, security problems can result if setuid is assigned to programs allowing reading and writing of files, or shell escapes. | Ask the SA for the weekly automated or manual process used to generate a list of setuid files on the system and compare it with the prior list. If no such process is in place, this is a finding. Review the process. If the process does not identify and report changes in setuid files, this is a finding. | Establish a weekly automated or manual process to generate a list of suid files on the system and compare it with the prior list. To create a list of suid files: # find / -perm -4000 > suid-file-list |
| V-804 | CCI-000318 | medium | The system must be checked weekly for unauthorized setgid files as well as unauthorized modification to authorized setgid files. | Files with the setgid bit set will allow anyone running these files to be temporarily assigned the group id of the file. While many system files depend on these attributes for proper operation, security problems can result if setgid is assigned to programs allowing reading and writing of files, or shell escapes. | Ask the SA if a weekly automated or manual process is used to generate a list of setgid files on the system and compare it with the prior list. If no such process is in place, this is a finding. | Establish a weekly automated or manual process to generate a list of setgid files on the system and compare it with the prior list. To create a list of setgid files: # find / -perm -2000 > setgid-file-list |
| V-805 | CCI-000225 | medium | Removable media, remote file systems, and any file system not containing approved setuid files must be mounted with the "nosuid" option. | The "nosuid" mount option causes the system to not execute setuid files with owner privileges. This option must be used for mounting any file system not containing approved setuid files. Executing setuid files from untrusted file systems, or file systems not containing approved setuid files, increases the opportunity for unprivileged users to attain unauthorized administrative access. | Check /etc/mtab and verify the "nosuid" mount option is used on file systems mounted from removable media, network shares, or any other file system not containing approved setuid or setgid files. If any of these files systems do not mount with the "nosuid" option, it is a finding. | Edit /etc/fstab and add the "nosuid" mount option to all file systems mounted from removable media or network shares, and any file system not containing approved setuid or setgid files. |
| V-806 | CCI-000366 | low | The sticky bit must be set on all public directories. | Failing to set the sticky bit on the public directories allows unauthorized users to delete files in the directory structure. The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage, (e.g., /tmp), and for directories requiring global read/write access. | Check all world-writable directories have the sticky bit set. Procedure: # find / -type d -perm -002 ! -perm -1000 > wwlist If the sticky bit is not set on a world-writable directory, this is a finding. | Set the sticky bit on all public directories. Procedure: # chmod 1777 /tmp (Replace /tmp with the public directory missing the sticky bit, if necessary.) |
| V-807 | CCI-000225 | medium | All public directories must be owned by root or an application account. | If a public directory has the sticky bit set and is not owned by a privileged UID, unauthorized users may be able to modify files created by others. The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage, (e.g., /tmp), and for directories requiring global read/write access. | Check the ownership of all public directories. Procedure: # find / -type d -perm -1002 -exec ls -ld {} \; If any public directory is not owned by root or an application user, this is a finding. | Change the owner of public directories to root or an application account. Procedure: # chown root /tmp (Replace root with an application user and/or /tmp with another public directory as necessary.) |
| V-808 | CCI-000366 | medium | The system and user default umask must be 077. | The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask can be represented as a 4-digit number, the first digit representing special access modes is typically ignored or required to be 0. This requirement applies to the globally configured system defaults and the user defaults for each account on the system. | Check global initialization files for the configured umask value. Procedure: # grep umask /etc/* Check local initialization files for the configured umask value. Procedure: # cut -d: -f6 /etc/passwd |xargs -n1 -IDIR find DIR -name ".*" -type f -maxdepth 1 -exec grep umask {} \; If the system and user default umask is not 077, this a finding. Note: If the default umask is 000 or allows for the creation of world-writable files this becomes a Severity Code I finding. | Edit local and global initialization files that contain "umask" and change them to use 077 instead of the current value. |
| V-812 | CCI-000162 | medium | System audit logs must be owned by root. | Failure to give ownership of system audit log files to root provides the designated owner and unauthorized users with the potential to access sensitive information. | Perform the following to determine the location of audit logs and then check the ownership. Procedure: # grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %U:%n If any audit log file is not owned by root, this is a finding. | Change the ownership of the audit log file(s). Procedure: # chown root <audit log file> |
| V-813 | CCI-000163 | medium | System audit logs must have mode 0640 or less permissive. | If a user can write to the audit logs, audit trails can be modified or destroyed and system intrusion may not be detected. System audit logs are those files generated from the audit system and do not include activity, error, or other log files created by application software. | Perform the following to determine the location of audit logs and then check the mode of the files. Procedure: # grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %a:%n If any audit log file has a mode more permissive than 0640, this is a finding. | Change the mode of the audit log directories/files. # chmod 0750 <audit directory> # chmod 0640 <audit file> |
| V-814 | CCI-000126 | medium | The audit system must be configured to audit failed attempts to access files and programs. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Verify auditd is configured to audit failed file access attempts. There must be an audit rule for each of the access syscalls logging all failed accesses (-F success=0) or there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S creat" | grep -e "-F success=0" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S creat" | grep -e "-F exit=-EPERM" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -e "-S creat" | grep -e "-F exit=-EACCES" If an "-S creat" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "creat" exist, then this is a finding. | Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs: either: -a exit,always -F arch=<ARCH> -S creat -F success=0 or both: -a exit,always -F arch=<ARCH> -S creat -F exit=-EPERM -a exit,always -F arch=<ARCH> -S creat -F exit=-EACCES Restart the auditd service. # service auditd restart |
| V-815 | CCI-000126 | medium | The audit system must be configured to audit files and programs deleted by the user. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system audit configuration to determine if file and directory deletions are audited. # cat /etc/audit.rules /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "unlink" If no results are returned, or the results do not contain "-S unlink", this is a finding. | Edit the audit.rules file and add the following line to enable auditing of deletions: -a exit,always -S unlink Restart the auditd service. # service auditd restart |
| V-818 | CCI-000126 | medium | The audit system must be configured to audit login, logout, and session initiation. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | The message types that are always recorded to /var/log/audit/audit.log include LOGIN,USER_LOGIN,USER_START,USER_END among others and do not need to be added to audit_rules. The log files /var/log/faillog and /var/log/lastlog must be protected from tampering of the login records. Procedure: #egrep "faillog|lastlog" /etc/audit/audit.rules|grep "-p (wa|aw)" If both /var/log/faillog and /var/log/lastlog entries do not exist, this is a finding. | Ensure logins Procedure: Modify /etc/audit/audit.rules to contain: -w /var/log/faillog -p wa -w /var/log/lastlog -p wa |
| V-819 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit.rules /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i " chmod " If "-S chmod" is not in the result, this is a finding | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S chmod Restart the auditd service. # service auditd restart |
| V-821 | CCI-000225 | medium | The inetd.conf file, xinetd.conf file, and the xinetd.d directory must be owned by root or bin. | Failure to give ownership of sensitive files or utilities to root provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration possibly weakening the system's security posture. | Check the owner of the xinetd configuration files. Procedure: # ls -lL /etc/xinetd.conf # ls -laL /etc/xinetd.d This is a finding if any of the above files or directories are not owned by root or bin. | Change the owner of the xinetd configuration files. # chown root /etc/xinetd.conf /etc/xinetd.d/* |
| V-822 | CCI-000225 | medium | The inetd.conf and xinetd.conf files must have mode 0440 or less permissive. | The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system. | Check the mode of the xinetd configuration files. Procedure: # ls -lL /etc/xinetd.conf # ls -lL /etc/xinetd.d If the mode of the file(s) is more permissive than 0640, this is a finding. | Change the mode of the xinetd configuration files. # chmod 0640 /etc/xinetd.conf /etc/xinetd.d/* |
| V-823 | CCI-000225 | medium | The services file must be owned by root or bin. | Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration possibly weakening the system's security posture. | Check the ownership of the services file. Procedure: # ls -lL /etc/services If the services file is not owned by root or bin, this is a finding. | Change the ownership of the services file to root or bin. Procedure: # chown root /etc/services |
| V-824 | CCI-000225 | medium | The services file must have mode 0644 or less permissive. | The services file is critical to the proper operation of network services and must be protected from unauthorized modification. Unauthorized modification could result in the failure of network services. | Check the mode of the services file. Procedure: # ls -lL /etc/services If the services file has a mode more permissive than 0644, this is a finding | Change the mode of the services file to 0644 or less permissive. Procedure: # chmod 0644 /etc/services |
| V-825 | CCI-000366 | low | Global initialization files must contain the "mesg -n" or "mesg n" commands. | If the "mesg -n" or "mesg n" command is not placed into the system profile, messaging can be used to cause a Denial of Service attack. | Check global initialization files for the presence of "mesg -n" or "mesg n". Procedure: # grep "mesg" etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* If no global initialization files contain "mesg -n" or "mesg n", this is a finding. | Edit /etc/profile or another global initialization script, and add the "mesg -n" command. |
| V-827 | CCI-000366 | medium | The hosts.lpd file (or equivalent) must not contain a ‘+’ character. | Having the '+' character in the hosts.lpd (or equivalent) file allows all hosts to use local system print resources. | RHEL uses "cups" print service. Verify remote host access is limited. Procedure: # grep -i Listen /etc/cups/cupsd.conf The /etc/cups/cupsd.conf file must not contain a Listen *:<port> or equivalent line. If the network address of the "Listen" line is unrestricted, this is a finding. # grep -i "Allow From" /etc/cups/cupsd.conf The "Allow From" line within the "<Location />" element should limit access to the printers to @LOCAL and specific hosts. If the "Allow From" line contains "All" this is a finding | Configure cups to use only the localhost or specified remote hosts. Procedure: Modify the /etc/cups/cupsd.conf file to "Listen" only to the local machine or a known set of hosts (i.e., Listen localhost:631). Modify the /etc/cups/cupsd.conf file "<Location />" element to "Deny From All" and "Allow from 127.0.0.1" or allowed host addresses. Restart cups: # service cups restart |
| V-828 | CCI-000225 | medium | The hosts.lpd (or equivalent) file must be owned by root, bin, sys, or lp. | Failure to give ownership of the hosts.lpd file to root, bin, sys, or lp provides the designated owner, and possible unauthorized users, with the potential to modify the hosts.lpd file. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers. | Check the ownership of the print service configuration file. Procedure: # ls -lL /etc/cups/printers.conf; If no print service configuration file is found, this is not applicable. If the owner of the file is not root, this is a finding | Change the owner of the /etc/cups/printers.conf to root. Procedure: # chown root /etc/cups/printers.conf |
| V-829 | CCI-000225 | medium | The hosts.lpd (or equivalent) must have mode 0644 or less permissive. | Excessive permissions on the hosts.lpd (or equivalent) file may permit unauthorized modification. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers. | Check the mode of the print service configuration file. Procedure: # ls -lL /etc/cups/printers.conf If no print service configuration file is found, this is not applicable. If the mode of the print service configuration file is more permissive than 0664, this is a finding. | Change the mode of the /etc/cups/printers.conf file to 0664 or less permissive. Procedure: # chmod 0664 /etc/cups/printers.conf |
| V-831 | CCI-000225 | medium | The alias file must be owned by root. | If the alias file is not owned by root, an unauthorized user may modify the file adding aliases to run malicious code or redirect e-mail. | Check the ownership of the alias files. Procedure: for sendmail: # ls -lL /etc/aliases # ls -lL /etc/aliases.db If all the files are not owned by root, this is a finding. for postfix: Verify the location of the alias file. # postconf alias maps This will return the location of the "aliases" file, by default "/etc/postfix/aliases" # ls -lL <postfix aliases file> # ls -lL <postfix aliases.db file> If all the files are not owned by root, this is a finding. | Change the owner of the /etc/aliases file to root. Procedure: for sendmail: # chown root /etc/aliases # chown root /etc/aliases.db for postfix # chown root /etc/postfix/aliases # chown root /etc/postfix/aliases.db |
| V-832 | CCI-000225 | medium | The alias file must have mode 0644 or less permissive. | Excessive permissions on the aliases file may permit unauthorized modification. If the alias file is modified by an unauthorized user, they may modify the file to run malicious code or redirect e-mail. | Check the permissions of the alias file. Procedure: for sendmail: # ls -lL /etc/aliases /etc/aliases.db If an alias file has a mode more permissive than 0644, this is a finding. for postfix: Verify the location of the alias file. # postconf alias maps This will return the location of the "aliases" file, by default "/etc/postfix/aliases" # ls -lL <postfix aliases file> <postfix aliases.db file> If an alias file has a mode more permissive than 0644, this is a finding. | Change the mode of the alias files as needed to function. No higher than 0644. Procedure: for sendmail: # chmod 0644 /etc/aliases /etc/aliases.db for postfix (assuming the default postfix directory): # chmod 0644 /etc/postfix/aliases /etc/postfix/aliases.db |
| V-833 | CCI-000225 | high | Files executed through a mail aliases file must be owned by root and must reside within a directory owned and writable only by root. | If a file executed through a mail aliases file is not owned and writable only by root, it may be subject to unauthorized modification. Unauthorized modification of files executed through aliases may allow unauthorized users to attain root privileges. | Verify the ownership of files referenced within the sendmail aliases file. Procedure: # more /etc/aliases Examine the aliases file for any utilized directories or paths. # ls -lL <directory or file path> Check the owner for any paths referenced. Check if the file or parent directory is owned by root. If not, this is a finding. | Edit the /etc/aliases file (alternatively, /usr/lib/sendmail.cf). Locate the entries executing a program. They will appear similar to the following line: Aliasname: : /usr/local/bin/ls (or some other program name) Ensure root owns the programs and the directory(ies) they reside in by using the chown command to change owner to root. Procedure: # chown root <file or directory name> |
| V-834 | CCI-000225 | medium | Files executed through a mail aliases file must have mode 0755 or less permissive. | If a file executed through a mail aliases file has permissions greater than 0755, it can be modified by an unauthorized user and may contain malicious code or instructions potentially compromising the system. | Examine the contents of the /etc/aliases file. Procedure: # more /etc/aliases Examine the aliases file for any referenced programs, which are specified with the pipe (|) symbol. # ls -lL <file referenced from aliases> Check the permissions for any paths referenced. If any file referenced from the aliases file has a mode more permissive than 0755, this is a finding. | Use the chmod command to change the access permissions for files executed from the alias file. For example: # chmod 0755 filename |
| V-835 | CCI-000366 | low | Sendmail logging must not be set to less than nine in the sendmail.cf file. | If Sendmail is not configured to log at level 9, system logs may not contain the information necessary for tracking unauthorized use of the sendmail service. | Check if sendmail logging is set to level nine: Procedure: for sendmail: # grep "O L" /etc/mail/sendmail.cf OR # grep LogLevel /etc/mail/sendmail.cf If logging is set to less than nine, this is a finding. for Postfix: This rule is not applicable to postfix which does not use "log levels" in the same fashion as sendmail. | Edit the sendmail.conf file, locate the "O L" or "LogLevel" entry and change it to 9. |
| V-836 | CCI-000126 | medium | The system syslog service must log informational and more severe SMTP service messages. | If informational and more severe SMTP service messages are not logged, malicious activity on the system may go unnoticed. | Check the syslog configuration file for mail.crit logging configuration. Procedure: # grep "mail\." /etc/syslog.conf If syslog is not configured to log critical sendmail messages ("mail.crit" or "mail.*"), this is a finding. | Check the syslog configuration file for mail.crit logging configuration. Procedure: # grep "mail\." /etc/syslog.conf If syslog is not configured to log critical sendmail messages ("mail.crit" or "mail.*"), this is a finding. |
| V-837 | CCI-000225 | medium | The SMTP service log file must be owned by root. | If the SMTP service log file is not owned by root, then unauthorized personnel may modify or delete the file to hide a system compromise. | Locate any mail log files by checking the syslog configuration file. Procedure: The check procedure is the same for both sendmail and Postfix. Identify any log files configured for the "mail" service (excluding mail.none) at any severity level and check the ownership # egrep "mail\.[^n][^/]*" /etc/syslog.conf|sed 's/^[^/]*//'|xargs ls -lL If any mail log file is not owned by root, this is a finding. | Change the ownership of the sendmail log file. Procedure: The fix procedure is the same for both sendmail and Postfix. # chown root <sendmail log file> |
| V-838 | CCI-000225 | medium | The SMTP service log file must have mode 0644 or less permissive. | If the SMTP service log file is more permissive than 0644, unauthorized users may be allowed to change the log file. | Check the mode of the SMTP service log file. Procedure: The check procedure is the same for both sendmail and Postfix. Identify any log files configured for the "mail" service (excluding mail.none) at any severity level and check the permissions # egrep "mail\.[^n][^/]*" /etc/syslog.conf|sed 's/^[^/]*//'|xargs ls -lL If the log file permissions are greater than 0644, this is a finding. | Change the mode of the SMTP service log file. Procedure: The fix procedure is the same for both sendmail and Postfix. # chmod 0644 <sendmail log file> |
| V-840 | CCI-000225 | medium | The ftpusers file must exist. | The ftpusers file contains a list of accounts not allowed to use FTP to transfer files. If this file does not exist, then unauthorized accounts can utilize FTP. | Check for the existence of the ftpusers file. Procedure: For gssftp: # ls -l /etc/ftpusers For vsftp: # ls -l /etc/vsftpd.ftpusers or # ls -l /etc/vsftpd/ftpusers If the appropriate ftpusers file for the running FTP service does not exist, this is a finding. | Create an ftpusers file appropriate for the running FTP service. For gssftp: Create an /etc/ftpusers file containing a list of accounts not authorized for FTP. For vsftp: Create an /etc/vfsftpd.ftpusers or /etc/vfsftpd/ftpusers (as appropriate) file containing a list of accounts not authorized for FTP. |
| V-841 | CCI-000225 | medium | The ftpusers file must contain account names not allowed to use FTP. | The ftpusers file contains a list of accounts not allowed to use FTP to transfer files. If the file does not contain the names of all accounts not authorized to use FTP, then unauthorized use of FTP may take place. | Check the contents of the ftpusers file. For gssftp: # more /etc/ftpusers For vsftp: # more /etc/vsftpd.ftpusers /etc/vfsftpd/ftpusers If the system has accounts not allowed to use FTP and not listed in the ftpusers file, this is a finding. | For gssftp: Add accounts not allowed to use FTP to the /etc/ftpusers file. For vsftp: Add accounts not allowed to use FTP to the /etc/vfsftpd.ftpusers or /etc/vfsftpd/ftpusers file (as appropriate). |
| V-842 | CCI-000225 | medium | The ftpusers file must be owned by root. | If the file ftpusers is not owned by root, an unauthorized user may modify the file to allow unauthorized accounts to use FTP. | Check the ownership of the ftpusers file. Procedure: For gssftp: # ls -l /etc/ftpusers For vsftp: # ls -l /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers If the ftpusers file is not owned by root, this is a finding | Change the owner of the ftpusers file to root. For gssftp: # chown root /etc/ftpusers For vsftp: # chown root /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers |
| V-843 | CCI-000225 | medium | The ftpusers file must have mode 0640 or less permissive. | Excessive permissions on the ftpusers file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized users to access the FTP service. | Check the permissions of the ftpusers file. Procedure: For gssftp: # ls -l /etc/ftpusers For vsftp: # ls -l /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers If the ftpusers file has a mode more permissive than 0640, this is a finding. | Change the mode of the ftpusers file to 0640. Procedure: For gssftp: # chmod 0640 /etc/ftpusers For vsftp: # chmod 0640 /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers |
| V-845 | CCI-000130 | low | The FTP daemon must be configured for logging or verbose mode. | The -l option allows basic logging of connections. The verbose (on HP) and the debug (on Solaris) allow logging of what files the ftp session transferred. This extra logging makes it possible to easily track which files are being transferred onto or from a system. If they are not configured, the only option for tracking is the audit files. The audit files are much harder to read. If auditing is not properly configured, then there would be no record at all of the file transfer transactions. | Find if logging is applied to the ftp daemon. The procedure depends on the implementation of ftpd used by the system. Procedures: For vsftpd: If vsftpd is started by xinetd: #grep vsftpd /etc/xinetd.d/* This will indicate the xinetd.d startup file #grep server_args <vsftpd xinetd.d startup file> This will indicate the vsftpd config file used when starting through xinetd. If the line is missing then "/etc/vsftpd/vsftpd.conf", the default config file, is used. #grep xferlog_enable <vsftpd config file> If "xferlog_enable" is missing or is not set to "yes", this is a finding. If vsftp is not started by xinetd: #grep xferlog_enable /etc/vsftpd/vsftpd.conf If "xferlog_enable" is missing or is not set to "yes", this is a finding. For gssftp: Find if the -l option will be applied when xinetd starts gssftp # grep server_args /etc/xinetd.d/gssftp If the line is missing or does not contain at least one -l, this is a finding. | Enable logging by changing ftpd startup or config files. Procedure: The procedure depends on the implementation of ftpd used by the system. For vsftpd: Ensure the server settings in "/etc/vsftpd.conf" (or other configuration file specified by the vaftpd xinetd.d startup file) contains: xferlog_enable = yes For gssftp: If the "disable" server setting is missing or set to "no" in "/etc/xinetd.d/gssftp" then ensure the server settings in "/etc/xinetd.d/gssftp" contains: server_args = -l The -l option may be added up to three times. Each -l will provide increasing verbosity on the log. Refer to the main page for ftpd for more information. For both if started using xinetd: If the "disable" server setting is missing or set to "no" in the /etc/xinetd.d startup file then ensure the server settings contains: log_on_success += DURATION USERID This will log the startup and shutdown of the daemon. log_on_failure += HOST USERID |
| V-846 | CCI-001475 | medium | Anonymous FTP must not be active on the system unless authorized. | Due to the numerous vulnerabilities inherent in anonymous FTP, it is not recommended. If anonymous FTP must be used on a system, the requirement must be authorized and approved in the system accreditation package. | Attempt to log into this host with a user name of anonymous and a password of guest (also try the password of guest@mail.com). If the logon is successful and the use of anonymous ftp has not been documented and approved by the IAO, this is a finding. Procedure: # ftp localhost Name: anonymous 530 Guest login not allowed on this machine. | Configure the FTP service to not permit anonymous logins. |
| V-847 | CCI-000366 | high | The TFTP daemon must operate in "secure mode" which provides access only to a single directory on the host file system. | Secure mode limits TFTP requests to a specific directory. If TFTP is not running in secure mode, it may be able to write to any file or directory and may seriously impair system integrity, confidentiality, and availability. | # grep server_args /etc/xinetd.d/tftp If the "-s" parameter is not specified, this is a finding. | Edit /etc/xinetd.d/tftp file and specify the "-s" parameter in server_args. |
| V-848 | CCI-000225 | high | The TFTP daemon must have mode 0755 or less permissive. | If TFTP runs with the setuid or setgid bit set, it may be able to write to any file or directory and may seriously impair system integrity, confidentiality, and availability. | Check the mode of the TFTP daemon. Procedure: # grep "server " /etc/xinetd.d/tftp # ls -lL <in.tftpd binary> If the mode of the file is more permissive than 0755, this is a finding. | Change the mode of the TFTP daemon. Procedure: # chmod 0755 <in.tftpd binary> |
| V-849 | CCI-000225 | medium | The TFTP daemon must be configured to vendor specifications, including a dedicated TFTP user account, a non-login shell such as /bin/false, and a home directory owned by the TFTP user. | If TFTP has a valid shell, it increases the likelihood someone could log on to the TFTP account and compromise the system. | Check the /etc/passwd file to determine if TFTP is configured properly. Procedure: Check if TFTP if used. # grep disable /etc/xinetd.d/tftp If the file does not exist or the returned line indicates "yes", then this is not a finding. Otherwise, if the returned line indicates "no" then TFTP is enabled and must use a dedicated "tftp" user. # grep user /etc/xinetd.d/tftp If the returned line indicates a user other than the dedicated "tftp" user, this is a finding. # grep tftp /etc/passwd If a "tftp" user account does not exist and TFTP is active, this is a finding. Check the user shell for the "tftp" user. If it is not /bin/false or equivalent, this is a finding. Check the home directory assigned to the "tftp" user. If no home directory is set, or the directory specified is not dedicated to the use of the TFTP service, this is a finding. | Configure TFTP to use a dedicated "tftp" user. Procedure: Create a dedicated "tftp" user account if none exists. Assign a non-login shell to the "tftp" user account, such as /bin/false. Assign a home directory to the "tftp" user account. Edit /etc/xinetd.d/tftp to have "tftp" as the value of the "user" parameter. |
| V-850 | CCI-000297 | medium | Any X Windows host must write .Xauthority files. | .Xauthority files ensure the user is authorized to access specific X Windows host. If .Xauthority files are not used, it may be possible to obtain unauthorized access to the X Windows host. | Check for .Xauthority or .xauth files being utilized by looking for such files in the home directory of a user. Procedure: Verify Xwindows is used on the system. # egrep "^x:5.*X11" /etc/inittab If no line is returned the boot process does not start Xwindows. If Xwindows is not configured to run, this rule is not applicable. Look for xauthority files in user home directory. # cd ~someuser # ls -la|egrep "(\.Xauthority|\.xauth)" If the .Xauthority or .xauth (followed by apparently random characters) files do not exist, ask the SA if the user is using Xwindows. If the user is utilizing Xwindows and none of these files exist, this is a finding. | Ensure the X Windows host is configured to write .Xauthority files into user home directories. Edit the Xaccess file. Ensure the line writing the .Xauthority file is uncommented. |
| V-867 | CCI-001435 | medium | The Network Information System (NIS) protocol must not be used. | Due to numerous security vulnerabilities existing within NIS, it must not be used. Possible alternative directory services are NIS+ and LDAP. | Perform the following to determine if NIS is active on the system: # ps -ef | grep ypbind If NIS is found active on the system, this is a finding. | Disable the use of NIS/NIS+. Use as a replacement Kerberos or LDAP. |
| V-899 | CCI-000225 | low | All interactive users must be assigned a home directory in the /etc/passwd file. | If users do not have a valid home directory, there is no place for the storage and control of files they own. | Use pwck to verify home directory assignments are present. # pwck If any user is not assigned a home directory, this is a finding. | Assign a home directory to any user without one. |
| V-900 | CCI-000225 | low | All interactive user home directories defined in the /etc/passwd file must exist. | If a user has a home directory defined that does not exist, the user may be given the / directory, by default, as the current working directory upon logon. This could create a Denial of Service because the user would not be able to perform useful tasks in this location. | Use pwck to verify assigned home directories exist. # pwck If any user's assigned home directory does not exist, this is a finding. | If a user has no home directory, determine why. If possible, delete accounts without a home directory. If the account is valid, then create the home directory using the appropriate system administration utility or manually. For instance: mkdir directoryname; copy the skeleton files into the directory; chown accountname for the new directory and the skeleton files. Document all changes. |
| V-901 | CCI-000225 | medium | All user home directories must have mode 0750 or less permissive. | Excessive permissions on home directories allow unauthorized access to user files. | Check the home directory mode of each user in /etc/passwd. Procedure: # cut -d: -f6 /etc/passwd|sort|uniq|xargs -n1 ls -ld If a user home directory's mode is more permissive than 0750, this is a finding. Note: Application directories are allowed and may need 0755 permissions (or greater) for correct operation. | Change the mode of user home directories to 0750 or less permissive. Procedure (example): # chmod 0750 <home directory> Note: Application directories are allowed and may need 0755 permissions (or greater) for correct operation. |
| V-902 | CCI-000225 | medium | All interactive user home directories must be owned by their respective users. | If users do not own their home directories, unauthorized users could access user files. | Check the ownership of each user home directory listed in the /etc/passwd file. Procedure: # cut -d : -f 6 /etc/passwd | xargs -n1 ls -ld If any user home directory is not owned by the assigned user, this is a finding. | Change the owner of a user's home directory to its assigned user. Procedure: # chown <user> <home directory> |
| V-903 | CCI-000225 | medium | All interactive user home directories must be group-owned by the home directory owner's primary group. | If the Group Identifier (GID) of the home directory is not the same as the GID of the user, this would allow unauthorized access to files. | Check the group ownership for each user in the /etc/passwd file. Procedure: # cut -d : -f 6 /etc/passwd | xargs -n1 ls -ld If any user home directory is not group-owned by the assigned user's primary group, this is a finding. Home directories for application accounts requiring different group ownership must be documented using site-defined procedures. | Change the group-owner for user home directories to the primary group of the assigned user. Procedure: Find the primary group of the user (GID) which is the fourth field of the user entry in /etc/passwd. # chgrp <GID> <user home directory> Document all changes. |
| V-904 | CCI-000225 | medium | All local initialization files must be owned by the home directorys user or root. | Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. | Check the ownership of local initialization files. Procedure: # ls -al /<usershomedirectory>/.login # ls -al /<usershomedirectory>/.cshrc # ls -al /<usershomedirectory>/.logout # ls -al /<usershomedirectory>/.profile # ls -al /<usershomedirectory>/.bash_profile # ls -al /<usershomedirectory>/.bashrc # ls -al /<usershomedirectory>/.bash_logout # ls -al /<usershomedirectory>/.env # ls -al /<usershomedirectory>/.dtprofile # ls -al /<usershomedirectory>/.dispatch # ls -al /<usershomedirectory>/.emacs # ls -al /<usershomedirectory>/.exrc # find /<usershomedirectory>/.dt ! -fstype nfs ! -user <username> -exec ls -ld {} \; If local initialization files are not owned by the home directory's user, this is a finding. | Change the ownership of the startup and login files in the user's directory to the user or root, as appropriate. Examine each user's home directory and verify all filenames beginning with "." are owned by the owner of the directory or root. If they are not, use the chown command to change the owner to the user and research the reasons why the owners were not assigned as required. Procedure: # chown username .filename Document all changes. |
| V-905 | CCI-000225 | medium | All local initialization files must have mode 0740 or less permissive. | Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. | Check the modes of local initialization files. Procedure: # ls -al /<usershomedirectory>/.bashrc # ls -al /<usershomedirectory>/.bash_login # ls -al /<usershomedirectory>/.bash_logout # ls -al /<usershomedirectory>/.bash_profile # ls -al /<usershomedirectory>/.cshrc # ls -al /<usershomedirectory>/.kshrc # ls -al /<usershomedirectory>/.login # ls -al /<usershomedirectory>/.logout # ls -al /<usershomedirectory>/.profile # ls -al /<usershomedirectory>/.tcshrc # ls -al /<usershomedirectory>/.env # ls -al /<usershomedirectory>/.dtprofile (permissions should be 0755) # ls -al /<usershomedirectory>/.dispatch # ls -al /<usershomedirectory>/.emacs # ls -al /<usershomedirectory>/.exrc # find /<usershomedirectory>/.dt ! -fstype nfs \( -perm -0002 -o -perm -0020 \) -exec ls -ld {} \; (permissions not to be more permissive than 0755) If local initialization files are more permissive than 0740 or the .dt directory is more permissive than 0755 or the .dtprofile file is more permissive than 0755, this is a finding. | Ensure user startup files have permissions of 0740 or more restrictive. Examine each user's home directory and verify all file names beginning with "." have access permissions of 0740 or more restrictive. If they do not, use the chmod command to correct the vulnerability. Procedure: # chmod 0740 .filename Note: The period is part of the file name and is required. |
| V-906 | CCI-000225 | medium | All run control scripts must have mode 0755 or less permissive. | If the startup files are writable by other users, they could modify the startup files to insert malicious commands into the startup files. | Check run control script modes. # cd /etc # ls -lL rc* # cd /etc/init.d # ls -l If any run control script has a mode more permissive than 0755, this is a finding. | Ensure all system startup files have mode 0755 or less permissive. Examine the "rc" files, and all files in the rc1.d (rc2.d, and so on) directories, and in the /etc/init.d directory to ensure they are not world-writable. If they are world-writable, use the chmod command to correct the vulnerability and research why they are world-writable. Procedure: # chmod 755 <startup file> |
| V-907 | CCI-000366 | medium | Run control scripts' executable search paths must contain only absolute paths. | The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths. | Verify run control scripts' library search paths. # grep -r PATH /etc/rc* /etc/init.d This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/), this is a relative path, this is a finding. | Edit the run control script and remove the relative path entry from the executable search path variable. |
| V-910 | CCI-000225 | high | Run control scripts must not execute world-writable programs or scripts. | World-writable files could be modified accidentally or maliciously to compromise system integrity. | Check the permissions on the files or scripts executed from system startup scripts to see if they are world-writable. Create a list of all potential run command level scripts. ls -l /sbin/init.d/* | tr '\011' ' ' | tr -s ' ' | cut -f 9,9 -d " " Create a list of world writeable files. # find / -perm -002 -type f >> worldWriteableFileList Determine if any of the world writeable files in worldWriteableFileList are called from the run command level scripts. Note: Depending upon the number of scripts vs world writeable files, it may be easier to inspect the scripts manually. # more `ls -l /sbin/init.d/* | tr '\011' ' ' | tr -s ' ' | cut -f 9,9 -d "` If any system startup script executes any file or script that is world-writable, this is a finding. | Remove the world-writable permission from programs or scripts executed by run control scripts. Procedure: # chmod o-w <program or script executed from run control script> |
| V-913 | CCI-000196 | medium | There must be no .netrc files on the system. | Unencrypted passwords for remote FTP servers may be stored in .netrc files. Policy requires passwords be encrypted in storage and not used in access scripts. | Check the system for the existence of any .netrc files. Procedure: # find / -name .netrc If any .netrc file exists, this is a finding. | Remove the .netrc file(s). Procedure: # find / -name .netrc # rm <.netrc file> |
| V-914 | CCI-000225 | low | All files and directories contained in interactive user home directories must be owned by the home directory's owner. | If users do not own the files in their directories, unauthorized users may be able to access them. Additionally, if files are not owned by the user, this could be an indication of system compromise. | For each user in the /etc/passwd file, check for the presence of files and directories within the user's home directory not owned by the home directory owner. Procedure: # find /<usershomedirectory> ! -fstype nfs ! -user <username> ! \( -name .bashrc -o -name .bash_login -o -name .bash_logout -o -name .bash_profile -o -name .cshrc -o -name .kshrc -o -name .login -o -name .logout -o -name .profile -o -name .tcshrc -o -name .env -o -name .dtprofile -o -name .dispatch -o -name .emacs -o -name .exrc \) -exec ls -ld {} \; If user home directories contain files or directories not owned by the home directory owner, this is a finding. | Change the ownership of files and directories in user home directories to the owner of the home directory. Procedure: # chown accountowner filename |
| V-915 | CCI-000225 | low | All files and directories contained in user home directories must have mode 0750 or less permissive. | Excessive permissions allow unauthorized access to user files. | For each user in the /etc/passwd file, check for files and directories with a mode more permissive than 0750. Procedure: # find /<usershomedirectory> ! -fstype nfs ! \( -name .bashrc -o -name .bash_login -o -name .bash_logout -o -name .bash_profile -o -name .cshrc -o -name .kshrc -o -name .login -o -name .logout -o -name .profile -o -name .tcshrc -o -name .env -o -name .dtprofile -o -name .dispatch -o -name .emacs -o -name .exrc \) \( -perm -0001 -o -perm -0002 -o -perm -0004 -o -perm -0020 -o -perm -2000 -o -perm -4000 \) -exec ls -ld {} \; If user home directories contain files or directories more permissive than 0750, this is a finding. | Change the mode of files and directories within user home directories to 0750. Procedure: # chmod 0750 filename Document all changes. |
| V-916 | CCI-000366 | medium | The /etc/shells (or equivalent) file must exist. | The shells file (or equivalent) lists approved default shells. It helps provide layered defense to the security approach by ensuring users cannot change their default shell to an unauthorized unsecure shell. | Verify /etc/shells exists. # ls -l /etc/shells If the file does not exist, this is a finding. | Create a /etc/shells file containing a list of valid system shells. Consult vendor documentation for an appropriate list of system shells. Procedure: # echo "/bin/bash" >> /etc/shells # echo "/bin/csh" >> /etc/shells (Repeat as necessary for other shells.) |
| V-917 | CCI-000366 | medium | All shells referenced in /etc/passwd must be listed in the /etc/shells file, except any shells specified for the purpose of preventing logins. | The shells file lists approved default shells. It helps provide layered defense to the security approach by ensuring users cannot change their default shell to an unauthorized unsecure shell. | Confirm the login shells referenced in the /etc/passwd file are listed in the /etc/shells file. Procedure: # for USHELL in `cut -d: -f7 /etc/passwd`; do if [ $(grep -c "${USHELL}" /etc/shells) == 0 ]; then echo "${USHELL} not in /etc/shells"; fi; done The /usr/bin/false, /bin/false, /dev/null, /sbin/nologin, /bin/sync, /sbin/halt, /sbin/shutdown, (and equivalents), and sdshell will be considered valid shells for use in the /etc/passwd file, but will not be listed in the /etc/shells file. If a shell referenced in /etc/passwd is not listed in the shells file, excluding the above mentioned shells, this is a finding. | Use the "chsh" utility or edit the /etc/passwd file and correct the error by changing the default shell of the account in error to an acceptable shell name contained in the /etc/shells file. Example: # chsh -s /bin/bash testuser |
| V-918 | CCI-000017 | medium | Accounts must be locked upon 35 days of inactivity. | On some systems, accounts with disabled passwords still allow access using rcp, remsh, or rlogin through equivalent remote hosts. All that is required is the remote host name and the user name match an entry in a hosts.equiv file and have a .rhosts file in the user directory. Using a shell called /bin/false or /dev/null (or an equivalent) will add a layered defense. Non-interactive accounts on the system, such as application accounts, may be documented exceptions. | Indications of inactive accounts are those that have no entries in the "last" log. Check the date in the "last" log to verify it is within the last 35 days or the maximum numbers of days set by the site if more restrictive. If an inactive account is not disabled via an entry in the password field in the /etc/passwd or /etc/shadow (or equivalent), check the /etc/passwd file to check if the account has a valid shell. The passwd command can also be used to list a status for an account. For example, the following may be used to provide status information on each local account: # cut -d: -f1 /etc/passwd | xargs -n1 passwd -S If an inactive account is found not disabled, this is a finding. | All inactive accounts will have /sbin/nologin (or an equivalent), as the default shell in the /etc/passwd file and have the password disabled. Examine the user accounts using the "last" command. Note the date of last login for each account. If any (other than system and application accounts) exceed 35 days or the maximum number of days set by the site, not to exceed 35 days, then disable the accounts using system-config-users tool. Alternately place a shell field of /sbin/nologin /bin/false or /dev/null in the passwd file entry for the account. |
| V-921 | CCI-000225 | medium | All shell files must be owned by root or bin. | If shell files are owned by users other than root or bin, they could be modified by intruders or malicious users to perform unauthorized actions. | Check the ownership of the system shells. # cat /etc/shells | xargs -n1 ls -l If any shell is not owned by root or bin, this is a finding. | Change the ownership of the shell with incorrect ownership. # chown root <shell> |
| V-922 | CCI-000225 | high | All shell files must have mode 0755 or less permissive. | Shells with world/group write permissions give the ability to maliciously modify the shell to obtain unauthorized access. | If /etc/shells exists, check the group ownership of each shell referenced. # cat /etc/shells | xargs -n1 ls -l Otherwise, check any shells found on the system. # find / -name "*sh" | xargs -n1 ls -l If a shell has a mode more permissive than 0755, this is a finding. | Change the mode of the shell. # chmod 0755 <shell> |
| V-923 | CCI-000318 | low | The system must be checked for extraneous device files at least weekly. | If an unauthorized device is allowed to exist on the system, there is the possibility the system may perform unauthorized operations. | Ask the SA for the automated or manual process used to check for extraneous device files. Review the process to determine if the system is checked for extraneous device files on a weekly basis. If no weekly automated or manual process is in place, this is a finding. If the process is not identifying extraneous device files, this is a finding. | Establish a weekly automated or manual process to create a list of device files on the system and determine if any files have been added, moved, or deleted since the last list was generated. A list of device files can be generated with this command: # find / -type b -o -type c > device-file-list |
| V-924 | CCI-000225 | medium | Device files and directories must only be writable by users with a system account or as configured by the vendor. | System device files in writable directories could be modified, removed, or used by an unprivileged user to control system hardware. | Find all world-writable device files existing anywhere on the system. Procedure: # find / -perm -2 -a \( -type b -o -type c \) > devicelist Check the permissions on the directories above subdirectories containing device files. If any of the device files or their parent directories are world-writable, excepting device files specifically intended to be world-writable such as /dev/null, this is a finding. | Remove the world-writable permission from the device file(s). Procedure: # chmod o-w <device file> Document all changes. |
| V-925 | CCI-000225 | medium | Device files used for backup must only be readable and/or writable by root or the backup user. | System backups could be accidentally or maliciously overwritten and destroy the ability to recover the system if a compromise should occur. Unauthorized users could also copy system files. | Check the system for world-writable device files. Procedure: # find / -perm -2 -a \( -type b -o -type c \) -exec ls -ld {} \; Ask the SA to identify any device files used for backup purposes. If any device file(s) used for backup are writable by users other than root or the designated backup user, this is a finding. | Use the chmod command to remove the world-writable bit from the backup device files. Procedure: # chmod o-w <back device filename> Document all changes. |
| V-928 | CCI-000225 | medium | The Network File System (NFS) export configuration file must be owned by root. | Failure to give ownership of the NFS export configuration file to root provides the designated owner and possible unauthorized users with the potential to change system configuration which could weaken the system's security posture. | Check the owner of the exports file. Example: # ls -lL /etc/exports If the export configuration file is not owned by root, this is a finding. | Change the owner of the exports file to root. Example: # chown root /etc/exports |
| V-929 | CCI-000225 | low | The Network File System (NFS) export configuration file must have mode 0644 or less permissive. | Excessive permissions on the NFS export configuration file could allow unauthorized modification of the file, which could result in Denial of Service to authorized NFS exports and the creation of additional unauthorized exports. | # ls -lL /etc/exports If the file has a mode more permissive than 0644, this is a finding. | # chmod 0644 /etc/exports |
| V-931 | CCI-000225 | medium | All Network File System (NFS) exported system files and system directories must be owned by root. | Failure to give ownership of sensitive files or directories to root provides the designated owner and possible unauthorized users with the potential to access sensitive information or change system configuration which could weaken the system's security posture. | Check for NFS exported file systems. Procedure: # cat /etc/exports For each file system displayed, check the ownership. # ls -lLa <exported file system path> If the files and directories are not owned by root, this is a finding. | Change the ownership of exported file systems not owned by root. Procedure: # chown root <path> |
| V-932 | CCI-000062 | medium | The Network File System (NFS) anonymous UID and GID must be configured to values without permissions. | When an NFS server is configured to deny remote root access, a selected UID and GID are used to handle requests from the remote root user. The UID and GID should be chosen from the system to provide the appropriate level of non-privileged access. | Check if the 'anonuid' and 'anongid' options are set correctly for exported file systems. List exported filesystems: # exportfs -v Each of the exported file systems should include an entry for the 'anonuid=' and 'anongid=' options set to "-1" or an equivalent (60001, 65534, or 65535). If appropriate values for 'anonuid' or 'anongid' are not set, this is a finding. | Edit "/etc/exports" and set the "anonuid=-1" and "anongid=-1" options for exports lacking it. Re-export the filesystems. |
| V-933 | CCI-000366 | medium | The Network File System (NFS) server must be configured to restrict file system access to local hosts. | The NFS access option limits user access to the specified level. This assists in protecting exported file systems. If access is not restricted, unauthorized hosts may be able to access the system's NFS exports. | Check the permissions on exported NFS file systems. Procedure: # exportfs -v If the exported file systems do not contain the 'rw' or 'ro' options specifying a list of hosts or networks, this is a finding. | Edit /etc/exports and add ro and/or rw options (as appropriate) specifying a list of hosts or networks which are permitted access. Re-export the file systems. |
| V-935 | CCI-000225 | medium | The Network File System (NFS) server must not allow remote root access. | If the NFS server allows root access to local file systems from remote hosts, this access could be used to compromise the system. | List the exports. # cat /etc/exports If any export contains "no_root_squash" or does not contain "root_squash" or "all_squash", this is a finding. | Edit the "/etc/exports" file and add "root_squash" (or "all_squash") and remove "no_root_squash". |
| V-936 | CCI-000225 | medium | The "nosuid" option must be enabled on all Network File System (NFS) client mounts. | Enabling the nosuid mount option prevents the system from granting owner or group-owner privileges to programs with the suid or sgid bit set. If the system does not restrict this access, users with unprivileged access to the local system may be able to acquire privileged access by executing suid or sgid files located on the mounted NFS file system. | Check the system for NFS mounts not using the "nosuid" option. Procedure: # mount -v | grep " type nfs " | egrep -v "nosuid" If the mounted file systems do not have the "nosuid" option, this is a finding. | Edit "/etc/fstab" and add the "nosuid" option for all NFS file systems. Remount the NFS file systems to make the change take effect. |
| V-940 | CCI-000366 | medium | The system must use an access control program. | Access control programs (such as TCP_WRAPPERS) provide the ability to enhance system security posture. | The tcp_wrappers package is provided with the RHEL distribution. Other access control programs may be available but will need to be checked manually. Determine if tcp_wrappers is installed. # rpm -qa | grep tcp_wrappers If no package is listed, this is a finding. | Install and configure the tcp_wrappers package. |
| V-941 | CCI-000126 | medium | The system's access control program must log each system access attempt. | If access attempts are not logged, then multiple attempts to log on to the system by an unauthorized user may go undetected. | The tcp_wrappers package is provided with the RHEL distribution. Other access control programs may be available but will need to be checked manually. Normally, tcpd logs to the mail facility in "/etc/syslog.conf". Determine if syslog is configured to log events by tcpd. Procedure: # more /etc/syslog.conf Look for entries similar to the following: mail.debug /var/adm/maillog mail.none /var/adm/maillog mail.* /var/log/mail authpriv.info /var/log/messages The above entries would indicate mail alerts are being logged. If no entries for mail exist, then tcpd is not logging this is a finding. If an alternate access control program is used and it does not provide logging of access attempts, this is a finding. | Configure the access restriction program to log every access attempt. Ensure the implementation instructions for tcp_wrappers are followed so system access attempts are recorded to the system log files. If an alternate application is used, it must support this function. |
| V-974 | CCI-000225 | medium | Access to the cron utility must be controlled using the cron.allow and/or cron.deny file(s). | The cron facility allows users to execute recurring jobs on a regular and unattended basis. The cron.allow file designates accounts allowed to enter and execute jobs using the cron facility. If neither cron.allow nor cron.deny exists, then any account may use the cron facility. This may open the facility up for abuse by system intruders and malicious users. | Check for the existence of the cron.allow and cron.deny files. # ls -lL /etc/cron.allow # ls -lL /etc/cron.deny If neither file exists, this is a finding. | Create /etc/cron.allow and/or /etc/cron.deny with appropriate content. |
| V-975 | CCI-000225 | medium | The cron.allow file must have mode 0600 or less permissive. | A readable and/or writable cron.allow file by users other than root could allow potential intruders and malicious users to use the file contents to help discern information, such as who is allowed to execute cron programs, which could be harmful to overall system and network security. | Check mode of the cron.allow file. Procedure: # ls -lL /etc/cron.allow If the file has a mode more permissive than 0600, this is a finding. | Change the mode of the cron.allow file to 0600. Procedure: # chmod 0600 /etc/cron.allow |
| V-976 | CCI-000225 | medium | Cron must not execute group-writable or world-writable programs. | If cron executes group-writable or world-writable programs, there is a possibility that unauthorized users could manipulate the programs with malicious intent. This could compromise system and network security. | List all cronjobs on the system. Procedure: # ls /var/spool/cron # ls /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls /etc/cron*|grep -v deny If cron jobs exist under any of the above directories, use the following command to search for programs executed by cron: # more <cron job file> Perform a long listing of each program file found in the cron file to determine if the file is group-writable or world-writable. # ls -la <cron program file> If cron executes group-writable or world-writable files, this is a finding. | Remove the world-writable and group-writable permissions from the cron program file(s) identified. # chmod go-w <cron program file> |
| V-977 | CCI-000225 | medium | Cron must not execute programs in, or subordinate to, world-writable directories. | If cron programs are located in or subordinate to world-writable directories, they become vulnerable to removal and replacement by malicious users or system intruders. | List all cronjobs on the system. Procedure: # ls /var/spool/cron # ls /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls /etc/cron*|grep -v deny If cron jobs exist under any of the above directories, use the following command to search for programs executed by at: # more <cron job file> Perform a long listing of each directory containing program files found in the cron file to determine if the directory is world-writable. # ls -ld <cron program directory> If cron executes programs in world-writable directories, this is a finding. | Remove the world-writable permission from the cron program directories identified. Procedure: # chmod o-w <cron program directory> |
| V-978 | CCI-000225 | medium | Crontab files must have mode 0600 or less permissive, and files in cron script directories must have mode 0700 or less permissive. | To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured. | Check the mode of the crontab files. # ls -lL /var/spool/cron/ # ls -lL /etc/cron.d/ # ls -lL /etc/crontab If any crontab file has a mode more permissive than 0600, this is a finding. | Change the mode of the crontab files. # chmod 0600 /var/spool/cron/* /etc/cron.d/* /etc/crontab |
| V-979 | CCI-000225 | medium | Cron and crontab directories must have mode 0755 or less permissive. | To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. | Check the mode of the crontab directories. Procedure: # ls -ld /var/spool/cron # ls -ld /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls -ld /etc/cron*|grep -v deny If the mode of any of the crontab directories is more permissive than 0755, this is a finding. | Change the mode of the crontab directories. # chmod 0755 <crontab directory> |
| V-980 | CCI-000225 | medium | Cron and crontab directories must be owned by root or bin. | Incorrect ownership of the cron or crontab directories could permit unauthorized users the ability to alter cron jobs and run automated jobs as privileged users. Failure to give ownership of cron or crontab directories to root or to bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture. | Check the owner of the crontab directories. Procedure: # ls -ld /var/spool/cron # ls -ld /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls -ld /etc/cron*|grep -v deny If the owner of any of the crontab directories is not root or bin, this is a finding. | Change the mode of the crontab directories. # chown root <crontab directory> |
| V-981 | CCI-000225 | medium | Cron and crontab directories must be group-owned by root, sys, bin or cron. | To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. Failure to give group-ownership of cron or crontab directories to a system group provides the designated group and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture. | Check the group owner of cron and crontab directories. Procedure: # ls -ld /var/spool/cron # ls -ld /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls -ld /etc/cron*|grep -v deny If a directory is not group-owned by root, sys, bin, or cron, this is a finding. | Change the group owner of cron and crontab directories. # chgrp root <crontab directory> |
| V-982 | CCI-000126 | medium | Cron logging must be implemented. | Cron logging can be used to trace the successful or unsuccessful execution of cron jobs. It can also be used to spot intrusions into the use of the cron facility by unauthorized and malicious users. | # grep cron /etc/syslog.conf If cron logging is not configured, this is a finding. Check the configured cron log file found in the cron entry of /etc/syslog (normally /var/log/cron). # ls -lL /var/log/cron If this file does not exist, or is older than the last cron job, this is a finding. | Edit /etc/syslog.conf and setup cron logging. |
| V-983 | CCI-000225 | medium | The cronlog file must have mode 0600 or less permissive. | Cron logs contain reports of scheduled system activities and must be protected from unauthorized access or manipulation. | Check the mode of the cron log file. Procedure: Check the configured cron log file found in the cron entry in /etc/syslog (normally /var/log/cron). # grep cron /etc/syslog.conf # ls -lL /var/log/cron If the mode is more permissive than 0600, this is a finding. | Change the mode of the cron log file. # chmod 0600 /var/log/cron |
| V-984 | CCI-000225 | medium | Access to the "at" utility must be controlled via the at.allow and/or at.deny file(s). | The "at" facility selectively allows users to execute jobs at deferred times. It is usually used for one-time jobs. The at.allow file selectively allows access to the "at" facility. If there is no at.allow file, there is no ready documentation of who is allowed to submit "at" jobs. | Check for the existence of at.allow and at.deny files. # ls -lL /etc/at.allow # ls -lL /etc/at.deny If neither file exists, this is a finding. | Create at.allow and/or at.deny files containing appropriate lists of users to be allowed or denied access to the "at" daemon. |
| V-985 | CCI-000225 | medium | The at.deny file must not be empty if it exists. | On some systems, if there is no at.allow file and there is an empty at.deny file, then the system assumes everyone has permission to use the "at" facility. This could create an insecure setting in the case of malicious users or system intruders. | # more /etc/at.deny If the at.deny file exists and is empty, this is a finding. | Add appropriate users to the at.deny file, or remove the empty at.deny file if an at.allow file exists. |
| V-986 | CCI-000225 | medium | Default system accounts (with the exception of root) must not be listed in the at.allow file or must be included in the at.deny file if the at.allow file does not exist. | Default accounts, such as bin, sys, adm, uucp, daemon, and others, should never have access to the "at" facility. This would create a possible vulnerability open to intruders or malicious users. | # more /etc/at.allow If default accounts (such as bin, sys, adm, and others) are listed in the at.allow file, this is a finding. | Remove the default accounts (such as bin, sys, adm, and others, traditionally UID less than 500) from the at.allow file. |
| V-987 | CCI-000225 | medium | The at.allow file must have mode 0600 or less permissive. | Permissions more permissive than 0600 (read, write and execute for the owner) may allow unauthorized or malicious access to the at.allow and/or at.deny files. | Check the mode of the at.allow file. # ls -lL /etc/at.allow If the at.allow file has a mode more permissive than 0600, this is a finding. | Change the mode of the at.allow file. # chmod 0600 /etc/at.allow |
| V-988 | CCI-000225 | medium | The "at" daemon must not execute group-writable or world-writable programs. | If the "at" facility executes world-writable or group-writable programs, it is possible for the programs to be accidentally or maliciously changed or replaced without the owner's intent or knowledge. This would cause a system security breach. | List the "at" jobs on the system. Procedure: # ls -la /var/spool/at For each "at" job file, determine which programs are executed. Procedure: # more <at job file> Check the each program executed by "at" for group- or world-writable permissions. Procedure: # ls -la <at program file> If "at" executes group or world-writable programs, this is a finding. | Remove group-write and world-write permissions from files executed by at jobs. Procedure: # chmod go-w <file> |
| V-989 | CCI-000225 | medium | The "at" daemon must not execute programs in, or subordinate to, world-writable directories. | If "at" programs are located in, or subordinate, to world-writable directories, they become vulnerable to removal and replacement by malicious users or system intruders. | List any "at" jobs on the system. Procedure: # ls /var/spool/at For each "at" job, determine which programs are executed by "at." Procedure: # more <at job file> Check the directory containing each program executed by "at" for world-writable permissions. Procedure: # ls -la <at program file directory> If "at" executes programs in world-writable directories, this is a finding. | Remove the world-writable permission from directories containing programs executed by "at". Procedure: # chmod o-w <at program directory> |
| V-993 | CCI-000178 | high | SNMP communities, users, and passphrases must be changed from the default. | Whether active or not, default SNMP passwords, users, and passphrases must be changed to maintain security. If the service is running with the default authenticators, then anyone can gather data about the system and the network and use the information to potentially compromise the integrity of the system or network(s). | Check the SNMP configuration for default passwords. Procedure: Examine the default install location /etc/snmp/snmpd.conf or: # find / -name snmpd.conf # more <snmpd.conf file> Identify any community names or user password configuration. If any community name or password is set to a default value such as "public", "private", "snmp-trap", or "password", or any value which does not meet DISA password requirements, this is a finding. | Change the default passwords. To change them, locate the file snmpd.conf. Edit the file. Locate the line system-group-read-community which has a default password of "public" and make the password something more secure and less guessable. Do the same for the lines reading system-group-write-community, read-community, write-community, trap and trap-community. Read the information in the file carefully. The trap is defining who to send traps to, for instance, by default. It is not a password, but the name of a host. |
| V-994 | CCI-000225 | medium | The snmpd.conf file must have mode 0600 or less permissive. | The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification. | Check the mode of the SNMP daemon configuration file. Procedure: Examine the default install location /etc/snmp/snmpd.conf or: # find / -name snmpd.conf # ls -lL <snmpd.conf file> If the snmpd.conf file has a mode more permissive than 0600, this is a finding. | Change the mode of the SNMP daemon configuration file to 0600. Procedure: # chmod 0600 <snmpd.conf> |
| V-995 | CCI-000225 | medium | Management Information Base (MIB) files must have mode 0640 or less permissive. | The ability to read the MIB file could impart special knowledge to an intruder or malicious user about the ability to extract compromising information about the system or network. | Check the modes for all Management Information Base (MIB) files on the system. Procedure: # find / -name *.mib # ls -lL <mib file> Any file returned with a mode 0640 or less permissive is a finding. | Change the mode of MIB files to 0640. Procedure: # chmod 0640 <mib file> |
| V-1010 | CCI-000366 | medium | Public directories must be the only world-writable directories and world-writable files must be located only in public directories. | World-writable files and directories make it easy for a malicious user to place potentially compromising files on the system. The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage, (e.g., /tmp), and for directories requiring global read/write access. | Check the system for world-writable files. Procedure: # find / -perm -2 -a \( -type d -o -type f \) -exec ls -ld {} \; If any world-writable files are located, except those required for system operation such as /tmp and /dev/null, this is a finding. | Remove or change the mode for any world-writable file on the system not required to be world-writable. Procedure: # chmod o-w <file> Document all changes |
| V-1011 | CCI-000134 | low | Inetd or xinetd logging/tracing must be enabled. | Inetd or xinetd logging and tracing allows the system administrators to observe the IP addresses connecting to their machines and what network services are being sought. This provides valuable information when trying to find the source of malicious users and potential malicious users. | The /etc/xinetd.conf file and each file in the /etc/xinetd.d directory file should be examined for the following: Procedure: log_type = SYSLOG authpriv log_on_success = HOST PID USERID EXIT log_on_failure = HOST USERID If xinetd is running and logging is not enabled, this is a finding. | Edit each file in the /etc/xinetd.d directory and the /etc/xinetd.conf file to contain: log_type = SYSLOG authpriv log_on_success = HOST PID USERID EXIT log_on_failure = HOST USERID The /etc/xinetd.conf file contains default values that will hold true for all services unless individually modified in the service's xinetd.d file. To make the new settings effective, restart the xinetd service: # service xinetd restart |
| V-1013 | CCI-000366 | high | The system must be configured to only boot from the system boot device. | The ability to boot from removable media is the same as being able to boot into single user, or maintenance, mode without a password. This ability could allow a malicious user to boot the system and perform changes with the potential to compromise or damage the system. It could also allow the system to be used for malicious purposes by a malicious anonymous user. | Determine if the system is configured to boot from devices other than the system startup media. If so, this is a finding. | Configure the system to only boot from system startup media. Procedure: On systems with a BIOS or system controller use the BIOS interface at startup to remove all but the proper boot device from the boot device list. |
| V-1021 | CCI-000032 | medium | The X server must have the correct options enabled. | Without the correct options enabled, the Xwindows system would be less secure and there would be no screen timeout. | Verify the options of the running Xwindows server are correct. Procedure: Get the running xserver information # ps -ef |grep X If the response contains /usr/bin/Xorg:0 /usr/bin/Xorg:0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7 this is indicative of Xorg starting through gdm. This is the default on RHEL. Examine the Xorg line: If the "-auth" option is missing this would be a finding. If the "-audit" option is missing or not set to 4, this is a finding. If the "-s" option is missing or greater than 15, this is a finding. If the response to the grep contains X:0 /usr/bin/X:0 this indicates the X server was started with the xinit command with no associated .xserverrc in the home directory of the user. No options are selected by default. This is a finding. Otherwise if there are options on the X:0 line: If the "-auth" option is missing this is a finding If the "-audit" option is missing or not set to 4, this is a finding. If the "-s" option is missing or greater than 15, this is a finding. | Enable the following options: -audit (at level 4), -auth and -s with 15 minutes as the timeout value. Procedure for gdm: Edit /etc/gdm/custom.conf and add the following: [server-Standard] name=Standard server command=/usr/bin/Xorg -br -audit 4 -s 15 chooser=false handled=true flexible=true priority=0 Procedure for xinit: Edit or create a .xserverrc file in the users home directory containing the startup script for xinit. This script must have an exec line with at least these options: exec /usr/bin/X -audit 4 -s 15 -auth <Xauth file> & The <Xauth file> is created using the "xauth" command and is customarily located in the users home directory with the name ".Xauthority". |
| V-1022 | CCI-000032 | medium | An X server must have none of the following options enabled: -ac, -core (except for debugging purposes), or -nolock. | These options will detract from the security of the Xwindows system. | Verify the options of the running Xwindows server are correct. Procedure: Get the running xserver information # ps -ef |grep X If the response contains /usr/bin/Xorg:0 /usr/bin/Xorg:0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7 this is indicative of Xorg starting through gdm. This is the default window manager on RHEL. If the "-ac" option is found, this is a finding. If the "-core" option is found, this is a finding. If the "-nolock" option is found, this is a finding. If the response to the grep contains X:0 /usr/bin/X:0 Examine the X:0 line: If the "-ac" option is found, this is a finding. If the "-core" option is found, this is a finding. If the "-nolock" option is found, this is a finding. | Disable the unwanted options: Procedure: For gdm: Remove the -ac, -core and -nolock options by creating a "command" entry in the /etc/gdm/custom.conf file with the options removed. For Xwindows started by xinit: Create or modify the .xserverrc script in the users home directory to remove the -ac, -core and -nolock options from the exec /usr/bin/X command. |
| V-1023 | CCI-000381 | medium | The system must not run an Internet Network News (INN) server. | INN servers access Usenet newsfeeds and store newsgroup articles. INN servers use the Network News Transfer Protocol (NNTP) to transfer information from the Usenet to the server and from the server to authorized remote hosts. If this function is necessary to support a valid mission requirement, its use must be authorized and approved in the system accreditation package. | # ps -ef | egrep "innd|nntpd" If an Internet Network News server is running, this is a finding. | Disable the INN server. |
| V-1025 | CCI-000225 | medium | The /etc/access.conf file must be owned by root. | The /etc/access.conf file contains entries restricting access from the system console by authorized System Administrators. If the file is owned by a user other than root, it could compromise the system. | Check access configuration ownership: # ls -lL /etc/security/access.conf If this file exists and is not owned by root, this is a finding. | Follow the correct configuration parameters for access configuration file. Use the chown command to configure it properly. (for example: # chown root /etc/security/access.conf ). |
| V-1026 | CCI-001436 | medium | The Samba Web Administration Tool (SWAT) must be restricted to the local host or require SSL. | SWAT is a tool used to configure Samba. It modifies Samba configuration, which can impact system security, and must be protected from unauthorized access. SWAT authentication may involve the root password, which must be protected by encryption when traversing the network. Restricting access to the local host allows for the use of SSH TCP forwarding, if configured, or administration by a web browser on the local system. | SWAT is a tool for configuring Samba and should only be found on a system with a requirement for Samba. If SWAT is used, it must be utilized with SSL to ensure a secure connection between the client and the server. Procedure: # grep -H "bin/swat" /etc/xinetd.d/*|cut -d: -f1 |xargs grep "only_from" If the value of the "only_from" line in the "xinetd.d" file which starts "/usr/sbin/swat" is not "localhost" or the equivalent, this is a finding. | Disable SWAT or require SWAT is only accessed via SSH. Procedure: If SWAT is not needed for operation of the system remove the SWAT package: # rpm -qa|grep swat Remove "samba-swat" or "samba3x-swat" depending on which one is installed # rpm --erase samba-swat or # rpm --erase samba3x-swat If SWAT is required but not at all times disable it when it is not needed. Modify the /etc/xinetd.d file for "swat" to contain a "disable = yes" line. To access using SSH: Follow vendor configuration documentation to create an stunnel for SWAT. |
| V-1027 | CCI-000225 | medium | The /etc/smb.conf file must be owned by root. | The /etc/smb.conf file allows access to other machines on the network and grants permissions to certain users. If it is owned by another user, the file may be maliciously modified and the Samba configuration could be compromised. | Check the ownership of the /etc/samba/smb.conf file. Procedure: # ls -l /etc/samba/smb.conf If an smb.conf file is not owned by root, this is a finding. | Change the ownership of the smb.conf file. Procedure: # chown root smb.conf |
| V-1028 | CCI-000225 | medium | The /etc/smb.conf file must have mode 0644 or less permissive. | If the "smb.conf" file has excessive permissions, the file may be maliciously modified and the Samba configuration could be compromised. | Check the mode of the smb.conf file. Procedure: # ls -lL /etc/samba/smb.conf If the "smb.conf" has a mode more permissive than 0644, this is a finding. | Change the mode of the smb.conf file to 0644 or less permissive. Procedure: # chmod 0644 smb.conf. |
| V-1029 | CCI-000225 | medium | The /etc/smbpasswd file must be owned by root. | If the "smbpasswd" file is not owned by root, it may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts. | Check the ownership of the "smbpasswd" file. # ls -l /etc/samba/passdb.tdb /etc/samba/secrets.tdb If the "smbpasswd" file is not owned by root, this is a finding. | Use the chown command to configure the files maintained by smbpasswd. For instance: # chown root /etc/samba/passdb.tdb /etc/samba/secrets.tdb |
| V-1030 | CCI-000225 | medium | The smb.conf file must use the "hosts" option to restrict access to Samba. | Samba increases the attack surface of the system and must be restricted to communicate only with systems requiring access. | Examine the "smb.conf" file. # more /etc/samba/smb.conf If the "hosts" option is not present to restrict access to a list of authorized hosts and networks, this is a finding. | Edit the "/etc/samba/smb.conf" file and set the "hosts" option to permit only authorized hosts to access Samba. |
| V-1032 | CCI-000198 | medium | Users must not be able to change passwords more than once every 24 hours. | The ability to change passwords frequently facilitates users reusing the same password. This can result in users effectively never changing their passwords. This would be accomplished by users changing their passwords when required and then immediately changing it to the original value. | Check the minimum time period between password changes for each user account is 1 day. # cat /etc/shadow | cut -d ':' -f 4 | grep -v 1 If any results are returned, this is a finding. | Change the minimum time period between password changes for each user account to 1 day. # passwd -n 1 <user name> |
| V-1046 | CCI-000197 | high | Root passwords must never be passed over a network in clear text form. | If a user accesses the root account (or any account) using an unencrypted connection, the password is passed over the network in clear text form and is subject to interception and misuse. This is true even if recommended procedures are followed by logging on to a named account and using the su command to access root. | Determine if root has logged in over an unencrypted network connection. First determine if root has logged in over a network. Procedure: # last | grep "^root " | egrep -v "reboot|console" | more Next determine if the SSH daemon is running. Procedure: # ps -ef |grep sshd If root has logged in over the network and sshd is not running, this is a finding. | Enable SSH on the system and use it for all remote connections used to attain root access |
| V-1047 | CCI-000770 | medium | The system must not permit root logins using remote access programs such as ssh. | Even though communications are encrypted, an additional layer of security may be gained by extending the policy of not logging directly on as root. In addition, logging in with a user-specific account preserves the audit trail. | Determine if the SSH daemon is configured to permit root logins. Procedure: # grep -v "^#" /etc/ssh/sshd_config | grep -i permitrootlogin If the PermitRootLogin entry is not found or is not set to "no", this is a finding. | Edit the sshd_config file and set the PermitRootLogin option to "no". |
| V-1048 | CCI-000225 | medium | Audio devices must have mode 0660 or less permissive. | Audio and video devices that are globally accessible have proven to be another security hazard. There is software that can activate system microphones and video devices connected to user workstations and/or X terminals. Once the microphone has been activated, it is possible to eavesdrop on otherwise private conversations without the victim being aware of it. This action effectively changes the user's microphone into a bugging device. | Check the mode of audio devices. # ls -lL /dev/audio* /dev/snd/* If the mode of audio devices are more permissive than 660, this is a finding. | Change the mode of audio devices. # chmod 0660 <audio device> |
| V-1049 | CCI-000225 | medium | Audio devices must be owned by root. | Audio and video devices globally accessible have proven to be another security hazard. There is software that can activate system microphones and video devices connected to user workstations and/or X terminals. Once the microphone has been activated, it is possible to eavesdrop on otherwise private conversations without the victim being aware of it. This action effectively changes the user's microphone into a bugging device. | Check the owner of audio devices. # ls -lL /dev/audio* /dev/snd/* If the owner of any audio device file is not root, this is a finding. | Change the owner of the audio device. # chown root <audio device> |
| V-1054 | CCI-000225 | medium | The /etc/access.conf file must have a privileged group owner. | Depending on the access restrictions of the /etc/access.conf file, if the group owner were not a privileged group, it could endanger system security. | Check access configuration group ownership: # ls -lL /etc/security/access.conf If this file exists and has a group-owner that is not a privileged user, this is a finding. | Use the chgrp command to ensure the group owner is root, sys, or bin. (for example: # chgrp root /etc/security/access.conf ). |
| V-1055 | CCI-000225 | medium | The /etc/access.conf file must have mode 0640 or less permissive. | If the access permissions are more permissive than 0640, system security could be compromised. | Check access configuration mode: # ls -lL /etc/security/access.conf If this file exists and has a mode more permissive than 0640, this is a finding. | Use the chmod command to set the permissions to 0640. (for example: # chmod 0640 /etc/security/access.conf ). |
| V-1056 | CCI-000225 | medium | The /etc/smb.conf file must be group-owned by root, bin, sys, or system. | If the group owner of the "smb.conf" file is not root or a system group, the file may be maliciously modified and the Samba configuration could be compromised. | Check the group ownership of the "smb.conf" file. Procedure: # ls -lL /etc/samba/smb.conf If the "smb.conf" file is not group-owned by root, bin, sys, or system, this is a finding. | Change the group owner of the smb.conf file. Procedure: # chgrp root smb.conf |
| V-1058 | CCI-000225 | medium | The smbpasswd file must be group-owned by root. | If the smbpasswd file is not group-owned by root, the smbpasswd file may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts. | Check "smbpasswd" ownership: # ls -lL /etc/samba/passdb.tdb /etc/samba/secrets.tdb If the "smbpasswd" file is not group-owned by root, this is a finding. | Use the chgrp command to ensure that the group owner of the smbpasswd file is root. For instance: # chgrp root /etc/samba/passdb.tdb /etc/samba/secrets.tdb |
| V-1059 | CCI-000225 | medium | The smbpasswd file must have mode 0600 or less permissive. | If the smbpasswd file has a mode more permissive than 0600, the smbpasswd file may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts. | Check the mode of files maintained using "smbpasswd". Procedure: # ls -lL /etc/samba/passdb.tdb /etc/samba/secrets.tdb If a "smbpasswd" maintained file has a mode more permissive than 0600, this is a finding. | Change the mode of the files maintained through smbpasswd to 0600. Procedure: # chmod 0600 /etc/samba/passdb.tdb /etc/samba/secrets.tdb |
| V-1061 | CCI-000225 | medium | Audio devices must be group-owned by root, sys, bin, or system. | Without privileged group owners, audio devices will be vulnerable to being used as eaves-dropping devices by malicious users or intruders to possibly listen to conversations containing sensitive information. | Check the group-owner of audio devices. Procedure: # ls -lL /dev/audio* /dev/snd/* If the group-owner of an audio device is not root, sys, bin, or system, this is a finding. | Change the group-owner of the audio device. Procedure: # chgrp root <audio device> |
| V-1062 | CCI-000366 | low | The root shell must be located in the / file system. | To ensure the root shell is available in repair and administrative modes, the root shell must be located in the / file system. | Determine if roots shell executable resides on a dedicated file system. Procedure: Find the location of the root users shell # grep "^root" /etc/passwd|cut -d: -f7|cut -d/ -f2 The result is the top level directory under / where the shell resides (ie. usr) Check if it is on a dedicated file system. # grep /<top level directory> /etc/fstab If /<top level directory> is on a dedicated file system, this is a finding. | Change the root account's shell to one present on the / file system. Procedure: Edit /etc/passwd and change the shell for the root account to one present on the / file system (such as /bin/sh, assuming /bin is not on a separate file system). If the system does not store shell configuration in the /etc/passwd file, consult vendor documentation for the correct procedure for the system. |
| V-4083 | CCI-000057 | medium | Graphical desktop environments provided by the system must automatically lock after 15 minutes of inactivity and the system must require users to re-authenticate to unlock the environment. Applications requiring continuous, real-time screen display (i.e., network management products) require the following and need to be documented with the IAO. -The logon session does not have administrator rights. -The display station (i.e., keyboard, monitor, etc.) is located in a controlled access area. | If graphical desktop sessions do not lock the session after 15 minutes of inactivity, requiring re-authentication to resume operations, the system or individual data could be compromised by an alert intruder who could exploit the oversight. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices as well as to graphical desktop environments provided to remote systems, including thin clients. | For the Gnome screen saver, check the idle_activation_enabled flag. Procedure: # gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/idle_activation_enabled If this does not return "true" and a documented exception has not been made by the IAO, this is a finding. | For the Gnome screen saver, set the idle_activation_enabled flag. Procedure: # gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type bool --set /apps/gnome-screensaver/idle_activation_enabled true |
| V-4084 | CCI-000200 | medium | The system must prohibit the reuse of passwords within five iterations. | If a user, or root, used the same password continuously or was allowed to change it back shortly after being forced to change it to something else, it would provide a potential intruder with the opportunity to keep guessing at one user's password until it was guessed correctly. | # ls /etc/security/opasswd If /etc/security/opasswd does not exist, then this is a finding. # grep password /etc/pam.d/system-auth| grep pam_unix.so | grep remember If the "remember" option in /etc/pam.d/system-auth is not 5 or greater, this is a finding. Check for system-auth-ac inclusions. # grep -c system-auth-ac /etc/pam.d/* If the system-auth-ac file is included anywhere # more /etc/pam.d/system-auth-ac | grep password | grep pam_unix.so | grep remember If in /etc/pam.d/system-auth-ac is referenced by another file and the "remember" option is not set to 5 or greater this is a finding. | Create the password history file. # touch /etc/security/opasswd # chown root:root /etc/security/opasswd # chmod 0600 /etc/security/opasswd Enable password history. If /etc/pam.d/system-auth references /etc/pam.d/system-auth-ac refer to the man page for system-auth-ac for a description of how to add options not configurable with authconfig. Edit /etc/pam.d/system-auth to include the remember option on the "password pam_unix" lines set to at least 5. |
| V-4087 | CCI-000225 | medium | User start-up files must not execute world-writable programs. | If start-up files execute world-writable programs, especially in unprotected directories, they could be maliciously modified to become trojans that destroy user files or otherwise compromise the system at the user, or higher, level. If the system is compromised at the user level, it is much easier to eventually compromise the system at the root and network level. | Check local initialization files for any executed world-writable programs or scripts and scripts executing from world writable directories. Procedure: For each home directory on the system make a list of files referenced within any local initialization script. Show the mode for each file and its parent directory. # FILES=".bashrc .bash_login .bash_logout .bash_profile .cshrc .kshrc .login .logout .profile .tcshrc .env .dtprofile .dispatch .emacs .exrc"; # for HOMEDIR in `cut -d: -f6 /etc/passwd|sort|uniq`;do for INIFILE in $FILES;do REFLIST=`egrep " [\"~]?/" ${HOMEDIR}/${INIFILE} 2>null|sed "s/.*\([~ \"]\/[\.0-9A-Za-z_\/\-]*\).*/\1/"`;for REFFILE in $REFLIST;do FULLREF=`echo $REFFILE|sed "s:\~:${HOMEDIR}:g"|sed "s:^\s*::g"`;dirname $FULLREF|xargs stat -c "dir:%a:%n";stat -c "file:%a:%n" $FULLREF;done;done;done|sort|uniq This command outputs a list of files and directories and their associated access modes. If any local initialization file executes a world-writable program or script or a script from a world-writable directory, this is a finding. | Remove the world-writable permission of files referenced by local initialization scripts, or remove the references to these files in the local initialization scripts. |
| V-4089 | CCI-000225 | medium | All system start-up files must be owned by root. | System start-up files not owned by root could lead to system compromise by allowing malicious users or applications to modify them for unauthorized purposes. This could lead to system and network compromise. | Check run control scripts' ownership. # ls -lL /etc/rc* /etc/init.d Alternatively: # find /etc -name "[SK][0-9]*"|xargs stat -L -c %U:%n If any run control script is not owned by root or bin, this is a finding. | Change the ownership of the run control script(s) with incorrect ownership. # find /etc -name "[SK][0-9]*"|xargs stat -L -c %U:%n|egrep -v "^root:"|cut -d: -f2|xargs chown root |
| V-4090 | CCI-000225 | medium | All system start-up files must be group-owned by root, sys, bin, other, or system. | If system start-up files do not have a group owner of root or a system group, the files may be modified by malicious users or intruders. | Check run control scripts' group ownership. Procedure: # ls -lL /etc/rc* /etc/init.d Alternatively: # find /etc -name "[SK][0-9]*"|xargs stat -L -c %G:%n|egrep -v "^(root|sys|bin|other):" If any run control script is not group-owned by root, sys, bin, or other system groups, this is a finding. | Change the group ownership of the run control script(s) with incorrect group ownership. Procedure: # chgrp root <run control script> # find /etc -name "[SK][0-9]*"|xargs stat -L -c %G:%n|egrep -v "^(root|sys|bin|other):"|cut -d: -f2|xargs chgrp root |
| V-4091 | CCI-000225 | medium | System start-up files must only execute programs owned by a privileged UID or an application. | System start-up files executing programs owned by other than root (or another privileged user) or an application indicating the system may have been compromised. | Determine the programs executed by system start-up files. Determine the ownership of the executed programs. # cat /etc/rc*/* /etc/init.d/* | more # ls -l <executed program> Alternatively: # for FILE in `egrep -r "/" /etc/rc.* /etc/init.d|awk '/^.*[^\/][0-9A-Za-z_\/]*/{print $2}'|egrep "^/"|sort|uniq`;do if [ -e $FILE ]; then stat -L -c '%U:%n' $FILE;fi;done This provides a list of files referenced by initialization scripts and their associated UIDs. If any file is run by an initialization file and is not owned by root, sys, bin, or in rare cases, an application account, this is a finding. | Change the ownership of the file executed from system startup scripts to root, bin, sys, or other. # chown root <executed file> |
| V-4246 | CCI-000213 | medium | System BIOS or system controllers supporting password protection must have administrator accounts/passwords configured, and no others. | A system's BIOS or system controller handles the initial startup of a system and its configuration must be protected from unauthorized modification. When the BIOS or system controller supports the creation of user accounts or passwords, such protections must be used and accounts/passwords only assigned to system administrators. Failure to protect BIOS or system controller settings could result in Denial of Service or compromise of the system resulting from unauthorized configuration changes. | On systems with a BIOS or system controller, verify a supervisor or administrator password is set. If a password is not set, this is a finding. If the BIOS or system controller supports user-level access in addition to supervisor/administrator access, determine if this access is enabled. If so, this is a finding. | Access the system's BIOS or system controller. Set a supervisor/administrator password if one has not been set. Disable a user-level password if one has been set. |
| V-4247 | CCI-000366 | high | The system must not use removable media as the boot loader. | Malicious users with removable boot media can gain access to a system configured to use removable media as the boot loader. | Ask the SA if the system uses removable media for the boot loader. If it does, this is a finding. | Configure the system to use a bootloader installed on fixed media. |
| V-4248 | CCI-000366 | high | For systems capable of using GRUB, the system must be configured with GRUB as the default boot loader unless another boot loader has been authorized, justified, and documented using site-defined procedures. | GRUB is a versatile boot loader used by several platforms that can provide authentication for access to the system or boot loader. | Determine if the system uses the GRUB boot loader; # ls -l /boot/grub/grub.conf If no grub.conf file exists, and the bootloader on the system has not been authorized, justified, and documented, this is a finding. | Configure the system to use the GRUB bootloader or document, justify, and authorize the alternate bootloader. |
| V-4249 | CCI-000213 | high | The system boot loader must require authentication. | If the system's boot loader does not require authentication, users with console access to the system may be able to alter the system boot configuration or boot the system into single user or maintenance mode, which could result in Denial of Service or unauthorized privileged access to the system. | Check the "/boot/grub/grub.conf" or "/boot/grub/menu.lst" files. # more /boot/grub/menu.lst Check for a password configuration line, such as: password --md5 <password-hash> This line should be just below the line beginning with "timeout". Please note <password-hash> will be replaced by the actual MD5 encrypted password. If the password line is not in either of the files, this is a finding. For any bootloader other than GRUB which has been authorized, justified and documented for use on the system refer to the vendor documentation on password support. If the bootloader does not support encrypted passwords, this is a finding. | The GRUB console boot loader can be configured to use an MD5 encrypted password by adding password --md5 password-hash to the "/boot/grub/grub.conf" file. Use "/sbin/grub-md5-crypt" to generate MD5 passwords from the command line. |
| V-4250 | CCI-000225 | medium | The system's boot loader configuration file(s) must have mode 0600 or less permissive. | File permissions greater than 0600 on boot loader configuration files could allow an unauthorized user to view or modify sensitive information pertaining to system boot instructions. | Check /boot/grub/grub.conf permissions: # ls -lL /boot/grub/grub.conf If /boot/grub/grub.conf has a mode more permissive than 0600, then this is a finding. For any bootloader other than GRUB which has been authorized, justified and documented for use on the system refer to the vendor documentation for the locatioin of the configuration file. If the bootloader configuration file has a mode more permissive than 0600, this is a finding. | Change the mode of the grub.conf file to 0600. # chmod 0600 /boot/grub/grub.conf |
| V-4255 | CCI-001208 | high | If the system boots from removable media, it must be stored in a safe or similarly secured container. | Storing the boot loader on removable media in an insecure location could allow a malicious user to modify the systems boot instructions or boot to an insecure operating system. | Ask the SA if the system boots from removable media. If so, ask if the boot media is stored in a secure container when not in use. If it is not, this is a finding. | Store the system boot media in a secure container when not in use. |
| V-4268 | CCI-000225 | high | The system must not have special privilege accounts, such as shutdown and halt. | If special privilege accounts are compromised, the accounts could provide privileges to execute malicious commands on a system. | Perform the following to check for unnecessary privileged accounts: # grep "^shutdown" /etc/passwd # grep "^halt" /etc/passwd # grep "^reboot" /etc/passwd If any unnecessary privileged accounts exist this is a finding. | Remove any special privilege accounts, such as shutdown and halt, from the /etc/passwd and /etc/shadow files using the "userdel" or "system-config-users" commands. |
| V-4269 | CCI-000012 | medium | The system must not have unnecessary accounts. | Accounts providing no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system. | Check the system for unnecessary user accounts. Procedure: # more /etc/passwd Obtain a list of authorized accounts from the IAO. If any unnecessary accounts are found on the system, this is a finding. | Remove all unnecessary accounts from the /etc/passwd file before connecting a system to the network. Other accounts that are associated with a service not in use should also be removed. |
| V-4273 | CCI-000225 | medium | The /etc/news/incoming.conf (or equivalent) must have mode 0600 or less permissive. | Excessive permissions on the "incoming.conf" file may allow unauthorized modification which could lead to Denial-of-Service to authorized users or provide access to unauthorized users. | RHEL uses the InternetNewsDaemon (innd) news server. The file corresponding to "/etc/news/hosts.nntp" is "/etc/news/incoming.conf". Check the permissions for "/etc/news/incoming.conf". # ls -lL /etc/news/incoming.conf If "/etc/news/incoming.conf" has a mode more permissive than 0600, this is a finding. | Change the mode of the "/etc/news/incoming.conf" file to 0600. # chmod 0600 /etc/news/incoming.conf |
| V-4274 | CCI-000225 | medium | The /etc/news/infeed.conf (or equivalent) must have mode 0600 or less permissive. | Excessive permissions on the "" file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users. | RHEL uses the InternetNewsDaemon (innd) news server. The file that corresponds to "/etc/news/hosts.nntp.nolimit" is "/etc/news/infeed.conf". Check the permissions for "/etc/news/infeed.conf". # ls -lL /etc/news/infeed.conf If "/etc/news/infeed.conf" has a mode more permissive than 0600, this is a finding. | Change the mode of "/etc/news/infeed.conf" to 0600. # chmod 0600 /etc/news/infeed.conf |
| V-4275 | CCI-000225 | medium | The /etc/news/readers.conf (or equivalent) must have mode 0600 or less permissive. | Excessive permissions on the readers.conf file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users. | Check the permissions for "/etc/news/readers.conf". # ls -lL /etc/news/readers.conf If /etc/news/readers.conf has a mode more permissive than 0600, this is a finding. | Change the mode of the /etc/news/readers.conf file to 0600. # chmod 0600 /etc/news/readers.conf |
| V-4276 | CCI-000225 | medium | The /etc/news/passwd.nntp file (or equivalent) must have mode 0600 or less permissive. | File permissions more permissive than 0600 for "/etc/news/passwd.nntp" may allow access to privileged information by system intruders or malicious users. | Check "/etc/news/passwd.nntp" permissions: # ls -lL /etc/news/passwd.nntp If "/etc/news/passwd.nntp" has a mode more permissive than 0600, this is a finding. | Change the mode of the "/etc/news/passwd.nntp" file. # chmod 0600 /etc/news/passwd.nntp |
| V-4277 | CCI-000225 | medium | Files in /etc/news must be owned by root or news. | If critical system files are not owned by a privileged user, system integrity could be compromised. | Check the ownership of the files in "/etc/news". Procedure: # ls -al /etc/news If any files are not owned by root or news, this is a finding. | Change the ownership of the files in "/etc/news" to root or news. Procedure: # chown root /etc/news/* |
| V-4278 | CCI-000225 | medium | The files in /etc/news must be group-owned by root or news. | If critical system files do not have a privileged group-owner, system integrity could be compromised. | Check "/etc/news" files group ownership: Procedure: # ls -al /etc/news If "/etc/news" files are not group-owned by root or news, this is a finding. | Change the group-owner of the files in "/etc/news" to root or news. Procedure: # chgrp root /etc/news/* |
| V-4295 | CCI-001436 | high | The SSH daemon must be configured to only use the SSHv2 protocol. | SSHv1 is not a DoD-approved protocol and has many well-known vulnerability exploits. Exploits of the SSH daemon could provide immediate root access to the system. | Locate the sshd_config file: # more /etc/ssh/sshd_config Examine the file. If the variables 'Protocol 2,1' or 'Protocol 1' are defined on a line without a leading comment, this is a finding. If the SSH server is F-Secure, the variable name for SSH 1 compatibility is 'Ssh1Compatibility', not 'protocol'. If the variable 'Ssh1Compatiblity' is set to 'yes', then this is a finding. | Edit the sshd_config file and set the "Protocol" setting to "2". If using the F-Secure SSH server, set the "Ssh1Compatibility" setting to "no". |
| V-4298 | CCI-000070 | medium | Remote consoles must be disabled or protected from unauthorized access. | The remote console feature provides an additional means of access to the system which could allow unauthorized access if not disabled or properly secured. With virtualization technologies, remote console access is essential as there is no physical console for virtual machines. Remote console access must be protected in the same manner as any other remote privileged access method. | Check /etc/securetty # more /etc/securetty If the file does not exist, or contains more than "console" or a single "tty" device this is a finding. | Create if needed and set the contents of /etc/securetty to a "console" or "tty" device. # echo console > /etc/securetty or # echo tty1 > /etc/securetty |
| V-4301 | CCI-001492 | medium | The system clock must be synchronized to an authoritative DoD time source. | To assure the accuracy of the system clock, it must be synchronized with an authoritative time source within DoD. Many system functions, including time-based login and activity restrictions, automated reports, system logs, and audit records depend on an accurate system clock. If there is no confidence in the correctness of the system clock, time-based functions may not operate as intended and records may be of diminished value. Authoritative time sources include authorized time servers within the enclave that synchronize with upstream authoritative sources. Specific requirements for the upstream synchronization of network time protocol (NTP) servers are covered in the Network Other Devices STIG. For systems located on isolated or closed networks, it is not necessary to synchronize with a global authoritative time source. If a global authoritative time source is not available to systems on an isolated network, a local authoritative time source must be established on this network and used by the systems connected to this network. This is necessary to provide the ability to correlate events and allow for the correct operation of time-dependent protocols between systems on the isolated network. If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events between systems will be necessary. If the system is completely isolated, this requirement is not applicable. | Check if NTP running: # ps -ef | egrep "xntpd|ntpd" Check if "ntpd -qg" scheduled to run: # grep "ntpd -qg" /var/spool/cron/* # grep "ntpd -qg" /etc/cron.d/* # grep "ntpd -qg" /etc/cron.daily/* # grep "ntpd -qg" /etc/cron.hourly/* # grep "ntpd -qg" /etc/cron.monthly/* # grep "ntpd -qg" /etc/cron.weekly/* If NTP is running or "ntpd -qg" is found: # more /etc/ntp.conf Confirm the timeservers and peers or multicast client (as applicable) are local or authoritative U.S. DoD sources appropriate for the level of classification which the network operates. If a non-local/non-authoritative time-server is used, this is a finding. | Use an authoritative local time server or a time server operated by the U.S. government. Ensure all systems in the facility feed from one or more local time servers which feed from the authoritative U.S. government time server. |
| V-4304 | CCI-000553 | medium | The root file system must employ journaling or another mechanism ensuring file system consistency. | File system journaling, or logging, can allow reconstruction of file system data after a system crash, preserving the integrity of data that may have otherwise been lost. Journaling file systems typically do not require consistency checks upon booting after a crash, which can improve system availability. Some file systems employ other mechanisms to ensure consistency also satisfying this requirement. | Logging should be enabled for those types of file systems not turning on logging by default. Procedure: # mount JFS, VXFS, HFS, XFS, reiserfs, EXT3 and EXT4 all turn logging on by default and will not be a finding. The ZFS file system uses other mechanisms to provide for file system consistency, and will not be a finding. For other file systems types, if the root file system does not support journaling this is a finding. If the 'nolog' option is set on the root file system that does support journaling, this is a finding. | Implement file system journaling for the root file system, or use a file system with other mechanisms to ensure file system consistency. If the root file system supports journaling, enable it. If the file system does not support journaling or another mechanism to ensure file system consistency, a migration to a different file system will be necessary. |
| V-4321 | CCI-001436 | medium | The system must not run Samba unless needed. | Samba is a tool used for the sharing of files and printers between Windows and UNIX operating systems. It provides access to sensitive files and, therefore, poses a security risk if compromised. | Check the system for a running Samba server. Procedure: # ps -ef |grep smbd If the Samba server is running, ask the SA if the Samba server is operationally required. If it is not, this is a finding. | If there is no functional need for Samba and the daemon is running, disable the daemon by killing the process ID as noted from the output of ps -ef |grep smbd. The samba package should also be removed or not installed if there is no functional requirement. Procedure: rpm -qa |grep samba This will show whether "samba" or "samba3x" is installed. To remove: rpm --erase samba or rpm --erase samba3x |
| V-4334 | CCI-000225 | medium | The /etc/sysctl.conf file must be owned by root. | The sysctl.conf file specifies the values for kernel parameters to be set on boot. These settings can affect the system's security. | Check /etc/sysctl.conf ownership. # ls -lL /etc/sysctl.conf If /etc/sysctl.conf is not owned by root, this is a finding. | Use the chown command to change the owner of /etc/sysctl.conf to root: # chown root /etc/sysctl.conf |
| V-4335 | CCI-000225 | medium | The /etc/sysctl.conf file must be group-owned by root. | The sysctl.conf file specifies the values for kernel parameters to be set on boot. These settings can affect the system's security. | Check /etc/sysctl.conf group ownership: # ls -lL /etc/sysctl.conf If /etc/sysctl.conf is not group-owned by root, this is a finding. | Use the chgrp command to change the group owner of /etc/sysctl.conf to root: # chgrp root /etc/sysctl.conf |
| V-4336 | CCI-000225 | medium | The /etc/sysctl.conf file must have mode 0600 or less permissive. | The sysctl.conf file specifies the values for kernel parameters to be set on boot. These settings can affect the system's security. | Check /etc/sysctl.conf permissions: # ls -lL /etc/sysctl.conf If /etc/sysctl.conf has a mode more permissive than 0600, this is a finding. | Use the chmod command to change the mode of the /etc/sysctl.conf file. # chmod 0600 /etc/sysctl.conf |
| V-4339 | CCI-000225 | high | The Linux NFS Server must not have the insecure file locking option. | Insecure file locking could allow for sensitive data to be viewed or edited by an unauthorized user. | Determine if an NFS server is running on the system by: # ps -ef |grep nfsd If an NFS server is running, confirm it is not configured with the insecure_locks option by: # exportfs -v The example below would be a finding: /misc/export speedy.example.com(rw,insecure_locks) | Remove the "insecure_locks" option from all NFS exports on the system. Procedure: Edit /etc/exports and remove all instances of the insecure_locks option. Re-export the file systems to make the setting take effect. # exportfs -a |
| V-4342 | CCI-000366 | high | The x86 CTRL-ALT-DELETE key sequence must be disabled. | Undesirable reboots can occur if the CTRL-ALT-DELETE key sequence is not disabled. Such reboots may cause a loss of data or loss of access to critical information. | Verify that reboot using the CTRL-ALT-DELETE key sequence has been disabled by performing: # grep ctrlaltdel /etc/inittab If the line returned does not specifiy "/usr/bin/logger" or is not commented out then this is a finding. | Ensure the CTRL-ALT-DELETE key sequence has been disabled and attempts to use the sequence are logged. In the /etc/inittab file replace: ca::ctrlaltdel:/sbin/shutdown -t3 -r now with ca:nil:ctrlaltdel:/usr/bin/logger -p security.info "Ctrl-Alt-Del was pressed" |
| V-4346 | CCI-000225 | medium | The Linux PAM system must not grant sole access to admin privileges to the first user who logs into the console. | If an unauthorized user has been granted privileged access while logged in at the console, the security posture of a system could be greatly compromised. Additionally, such a situation could deny legitimate root access from another terminal. | Ensure the pam_console.so module is not configured in any files in /etc/pam.d by: # cd /etc/pam.d # grep pam_console.so * Or # ls -la /etc/security/console.perms If either the pam_console.so entry or the file /etc/security/console.perms is found then this is a finding. | Configure PAM to not grant sole access of administrative privileges to the first user logged in at the console. Identify any instances of pam_console. # cd /etc/pam.d # grep pam_console.so * For any files containing an un-commented reference to pam_console.so, edit the file and remove or comment out the reference. Remove the console.perms file if it exists: # rm /etc/security/console.perms |
| V-4357 | CCI-000366 | medium | Audit logs must be rotated daily. | Rotate audit logs daily to preserve audit file system space and to conform to the DoD/DISA requirement. If it is not rotated daily and moved to another location, then there is more of a chance for the compromise of audit data by malicious users. | Check for any crontab entries that rotate audit logs. Procedure: # crontab -l If such a cron job is found, this is not a finding. Otherwise, query the SA. If there is a process automatically rotating audit logs, this is not a finding. If the SA manually rotates audit logs, this is a finding, because if the SA is not there, it will not be accomplished. If the audit output is not archived daily, to tape or disk, this is a finding. This can be ascertained by looking at the audit log directory and, if more than one file is there, or if the file does not have today's date, this is a finding. | Configure a cron job or other automated process to rotate the audit logs on a daily basis. |
| V-4358 | CCI-000225 | medium | The cron.deny file must have mode 0600 or less permissive. | If file permissions for cron.deny are more permissive than 0600, sensitive information could be viewed or edited by unauthorized users. | Check the mode of the cron.deny file. # ls -lL /etc/cron.deny If the cron.deny file does not exist this is not a finding. If the cron.deny file exists and the mode is more permissive than 0600, this is a finding. | Change the mode of the cron.deny file. # chmod 0600 /etc/cron.deny |
| V-4360 | CCI-000225 | low | Cron programs must not set the umask to a value less restrictive than 077. | The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 700 or less permissive. Although umask is often represented as a 4-digit octal number, the first digit representing special access modes is typically ignored or required to be 0. | Determine if there are any crontabs by viewing a long listing of the directory. If there are crontabs, examine them to determine what cron jobs exist. Check for any programs specifying an umask more permissive than 077: Procedure: # ls -lL /var/spool/cron # ls -lL /etc/cron.d /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls -lL /etc/cron.*|grep -v deny # cat <crontab file> # grep umask <cron program> If there are no cron jobs present, this vulnerability is not applicable. If any cron job contains an umask more permissive than 077, this is a finding. | Edit cron script files and modify the umask to 077. |
| V-4361 | CCI-000225 | medium | The cron.allow file must be owned by root, bin, or sys. | If the owner of the cron.allow file is not set to root, bin, or sys, the possibility exists for an unauthorized user to view or to edit sensitive information. | # ls -lL /etc/cron.allow If the cron.allow file is not owned by root, sys, or bin, this is a finding. | # chown root /etc/cron.allow |
| V-4364 | CCI-000225 | medium | The "at" directory must have mode 0755 or less permissive. | If the "at" directory has a mode more permissive than 0755, unauthorized users could be allowed to view or to edit files containing sensitive information within the "at" directory. Unauthorized modifications could result in Denial of Service to authorized "at" jobs. | Check the mode of the "at" directory. Procedure: # ls -ld /var/spool/at If the directory mode is more permissive than 0755, this is a finding. | Change the mode of the "at" directory to 0755. Procedure: # chmod 0755 <at directory> |
| V-4365 | CCI-000225 | medium | The at directory must be owned by root, bin, sys, daemon, or cron. | If the owner of the "at" directory is not root, bin, or sys, unauthorized users could be allowed to view or edit files containing sensitive information within the directory. | Check the ownership of the "at" directory: Procedure: # ls -ld /var/spool/at If the directory is not owned by root, sys, bin, daemon, or cron, this is a finding. Fix Text: Change the owner of the "at" directory to root, bin, sys, or system. | Change the owner of the "at" directory to root, bin, sys, or system. Procedure: # chown <root or other system account> <"at" directory> |
| V-4366 | CCI-000225 | medium | "At" jobs must not set the umask to a value less restrictive than 077. | The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 700 or less permissive. Although umask is often represented as a 4-digit number, the first digit representing special access modes is typically ignored or required to be 0. | Determine what "at" jobs exist on the system. Procedure: # ls /var/spool/at If there are no "at" jobs present, this is not applicable. Determine if any of the "at" jobs or any scripts referenced execute the "umask" command. Check for any umask setting more permissive than 077. # grep umask <at job or referenced script> If any "at" job or referenced script sets umask to a value more permissive than 077, this is a finding. | Edit "at" jobs or referenced scripts to remove "umask" commands that set umask to a value less restrictive than 077. |
| V-4367 | CCI-000225 | medium | The at.allow file must be owned by root, bin, or sys. | If the owner of the at.allow file is not set to root, bin, or sys, unauthorized users could be allowed to view or edit sensitive information contained within the file. | # ls -lL /etc/at.allow If the at.allow file is not owned by root, sys, or bin, this is a finding. | Change the owner of the at.allow file. # chown root /etc/at.allow |
| V-4368 | CCI-000225 | medium | The at.deny file must be owned by root, bin, or sys. | If the owner of the at.deny file is not set to root, bin, or sys, unauthorized users could be allowed to view or edit sensitive information contained within the file. | # ls -lL /etc/at.deny If the at.deny file is not owned by root, sys, or bin, this is a finding. | Change the owner of the at.deny file. # chown root /etc/at.deny |
| V-4369 | CCI-000225 | medium | The traceroute command owner must be root. | If the traceroute command owner has not been set to root, an unauthorized user could use this command to obtain knowledge of the network topology inside the firewall. This information may allow an attacker to determine trusted routers and other network information potentially leading to system and network compromise. | # ls -lL /bin/traceroute If the traceroute command is not owned by root, this is a finding. | Change the owner of the traceroute command to root. Example: # chown root /bin/traceroute |
| V-4370 | CCI-000225 | medium | The traceroute command must be group-owned by sys, bin, root, or system. | If the group owner of the traceroute command has not been set to a system group, unauthorized users could have access to the command and use it to gain information regarding a network's topology inside of the firewall. This information may allow an attacker to determine trusted routers and other network information potentially leading to system and network compromise. | Check the group ownership of the traceroute file. Procedure: # ls -lL /bin/traceroute If the traceroute command is not group-owned by root, sys, bin, or system, this is a finding. | Change the group-owner of the traceroute command to root. Procedure: # chgrp root /bin/traceroute |
| V-4371 | CCI-000225 | medium | The traceroute file must have mode 0700 or less permissive. | If the mode of the traceroute executable is more permissive than 0700, malicious code could be inserted by an attacker and triggered whenever the traceroute command is executed by authorized users. Additionally, if an unauthorized user is granted executable permissions to the traceroute command, it could be used to gain information about the network topology behind the firewall. This information may allow an attacker to determine trusted routers and other network information potentially leading to system and network compromise. | # ls -lL /bin/traceroute If the traceroute command has a mode more permissive than 0700, this is a finding. | Change the mode of the traceroute command. # chmod 0700 /bin/traceroute |
| V-4382 | CCI-000225 | high | Administrative accounts must not run a web browser, except as needed for local service administration. | If a web browser flaw is exploited while running as a privileged user, the entire system could be compromised. Specific exceptions for local service administration should be documented in site-defined policy. These exceptions may include HTTP(S)-based tools used for the administration of the local system, services, or attached devices. Examples of possible exceptions are HP’s System Management Homepage (SMH), the CUPS administrative interface, and Sun's StorageTek Common Array Manager (CAM) when these services are running on the local system. | Look in the root account home directory for a .mozilla directory. If none exists, this is not a finding. If there is one, verify with the root users and the IAO the intent of the browsing. If the browsing is not limited to authorized local services administration, this is a finding. | Enforce policy requiring administrative accounts use web browsers only for local service administration. |
| V-4384 | CCI-000366 | low | The SMTP service's SMTP greeting must not provide version information. | The version of the SMTP service can be used by attackers to plan an attack based on vulnerabilities present in the specific version. | To check for the version of either sendmail or Postfix being displayed in the greeting: # telnet localhost 25 If a version number is displayed, this is a finding. | Ensure sendmail or Postfix has been configured to mask the version information. Procedure for sendmail: Change the O SmtpGreetingMessage line in the /etc/mail/sendmail.cf file as noted below: O SmtpGreetingMessage=$j Sendmail $v/$Z; $b change it to: O SmtpGreetingMessage= Mail Server Ready ; $b for Postfix: Examine the "smtpd_banner" line of /etc/postfix/main.conf and remove any "$mail_version" entry on it or comment the entire "smtpd_banner" line to use the default value which does not display the version information. |
| V-4385 | CCI-000366 | medium | The system must not use .forward files. | The .forward file allows users to automatically forward mail to another system. Use of .forward files could allow the unauthorized forwarding of mail and could potentially create mail loops which could degrade system performance. | Check forwarding capability from sendmail. Procedure: grep "0 ForwardPath" /etc/mail/sendmail.cf If the entry contains a file path, this is a finding. Search for any .forward in users home directories on the system by: # for pwline in `cut -d: -f1,6 /etc/passwd`; do homedir=`echo ${pwline}|cut -d: -f2`;username=`echo ${pwline} | cut -d: -f1`;echo $username `stat -c %n $homedir/.forward 2>null`; done|egrep "\.forward" If any users have a .forward file in their home directory, this is a finding. | Disable forwarding for sendmail and remove .forward files from the system Procedure: Edit the /etc/mail/sendmail.mc file to change the ForwardPath entry to a null path by adding the line define(`confFORWARD_PATH`,`') rebuild the sendmail.cf file. Remove all .forward files on the system # find / -name .forward -delete |
| V-4387 | CCI-000225 | high | Anonymous FTP accounts must not have a functional shell. | If an anonymous FTP account has been configured to use a functional shell, attackers could gain access to the shell if the account is compromised. | Check the shell for the anonymous FTP account. Procedure: # grep "^ftp" /etc/passwd This is a finding if the seventh field is empty (the entry ends with a ':') or if the seventh field does not contain one of the following: /bin/false /dev/null /usr/bin/false /bin/true /sbin/nologin | Configure anonymous FTP accounts to use a non-functional shell. If necessary, edit the /etc/passwd file to remove any functioning shells associated with the ftp account and replace them with non-functioning shells, such as /dev/null. |
| V-4392 | CCI-001208 | medium | If the system is a Network Management System (NMS) server, it must only run the NMS and any software required by the NMS. | Installing extraneous software on a system designated as a dedicated Network Management System (NMS) server poses a security threat to the system and the network. Should an attacker gain access to the NMS through unauthorized software, the entire network may be susceptible to malicious activity. | Ask the SA if this is an NMS server. If it is an NMS server, then ask what other applications run on it. If there is anything other than network management software and DBMS software used only for the storage and inquiry of NMS data, this is a finding. | Ensure only authorized software is loaded on a designated NMS server. Authorized software is limited to the NMS software itself, a database management system for the NMS server if necessary, and network management software. |
| V-4393 | CCI-000225 | medium | The /etc/syslog.conf file must be owned by root. | If the /etc/syslog.conf file is not owned by root, unauthorized users could be allowed to view, edit, or delete important system messages handled by the syslog facility. | Check /etc/syslog.conf ownership: # ls -lL /etc/syslog.conf If /etc/syslog.conf is not owned by root, this is a finding. | Use the chown command to set the owner to root. # chown root /etc/syslog.conf |
| V-4394 | CCI-000225 | medium | The /etc/syslog.conf file must be group-owned by root, bin, sys, or system. | If the group owner of /etc/syslog.conf is not root, bin, or sys, unauthorized users could be permitted to view, edit, or delete important system messages handled by the syslog facility. | Check /etc/syslog.conf group ownership. Procedure: # ls -lL /etc/syslog.conf If /etc/syslog.conf is not group owned by root, sys, bin, or system, this is a finding. | Procedure: # chgrp root /etc/syslog.conf |
| V-4395 | CCI-000366 | medium | The system must only use remote syslog servers (log hosts) that is justified and documented using site-defined procedures. | If a remote log host is in use and it has not been justified and documented with the IAO, sensitive information could be obtained by unauthorized users without the SA's knowledge. A remote log host is any host to which the system is sending syslog messages over a network. | Examine the syslog.conf file for any references to remote log hosts. # grep -v "^#" /etc/syslog.conf | grep '@' Destination locations beginning with an '@' represent log hosts. If the log host name is a local alias such as "loghost", consult the /etc/hosts or other name databases as necessary to obtain the canonical name or address for the log host. Determine if the host referenced is a log host documented using site-defined procedures. If an undocumented log host is referenced, this is a finding. | Remove or document the referenced undocumented log host. |
| V-4397 | CCI-000366 | medium | The system must be configured with a default gateway for IPv4 if the system uses IPv4, unless the system is a router. | If a system has no default gateway defined, the system is at increased risk of man-in-the-middle, monitoring, and Denial of Service attacks. | Check the system for an IPv4 default route. If the system is a VM host and acts as a router solely for the benefit of its client systems, then this rule is not applicable. Procedure: # netstat -r |grep default If a default route is not defined, this is a finding. | Set a default gateway for IPv4. |
| V-4398 | CCI-001208 | medium | A system used for routing must not run other network services or applications. | Installing extraneous software on a system designated as a dedicated router poses a security threat to the system and the network. Should an attacker gain access to the router through the unauthorized software, the entire network is susceptible to malicious activity. | If the system is a VM host and acts as a router solely for the benefit of its client systems, then this rule is not applicable. Ask the SA if the system is a designated router. If it is not, this is not applicable. Check the system for non-routing network services. Procedure: # netstat -a | grep -i listen # ps -ef If non-routing services, including Web servers, file servers, DNS servers, or applications servers, but excluding management services such as SSH and SNMP, are running on the system, this is a finding. | Ensure only authorized software is loaded on a designated router. Authorized software will be limited to the most current version of routing protocols and SSH for system administration purposes. |
| V-4399 | CCI-001436 | high | The system must not use UDP for NIS/NIS+. | Implementing Network Information Service (NIS) or NIS+ under UDP may make the system more susceptible to a Denial of Service attack and does not provide the same quality of service as TCP. | If the system does not use NIS or NIS+, this is not applicable. Check if NIS or NIS+ is implemented using UDP. Procedure: # rpcinfo -p | grep yp | grep udp If NIS or NIS+ is implemented using UDP, this is a finding. | Configure the system to not use UDP for NIS and NIS+. Consult vendor documentation for the required procedure. |
| V-4427 | CCI-000366 | medium | All .rhosts, .shosts, or host.equiv files must only contain trusted host-user pairs. | If these files are not properly configured, they could allow malicious access by unknown malicious users from untrusted hosts who could compromise the system. | Locate and examine all r-commands access control files. Procedure: # find / -name .rhosts # more /<directorylocation>/.rhosts # find / -name .shosts # more /<directorylocation>/.shosts # find / -name hosts.equiv # more /<directorylocation>/hosts.equiv # find / -name shosts.equiv # more /<directorylocation>/shosts.equiv If any .rhosts, .shosts, hosts.equiv, or shosts.equiv file contains other than host-user pairs, this is a finding. | If possible, remove the .rhosts, .shosts, hosts.equiv, and shosts.equiv files. If the files are required, remove any content from the files except for necessary host-user pairs. |
| V-4428 | CCI-000225 | medium | All .rhosts, .shosts, .netrc, or hosts.equiv files must be accessible by only root or the owner. | If these files are accessible by users other than root or the owner, they could be used by a malicious user to set up a system compromise. | Procedure: # ls -l /etc/hosts.equiv # ls -l /etc/ssh/shosts.equiv # find / -name .rhosts # ls -al <home directory>/.rhosts # find / -name .shosts # ls -al <home directory>/.shosts # find / -name .netrc # ls -al <home directory>/.netrc If the .rhosts, .shosts, hosts.equiv, or shosts.equiv files have permissions greater than 600, then this is a finding. If the /etc/hosts.equiv, or /etc/ssh/shosts.equiv files are not owned by root, this is a finding. Any .rhosts, .shosts and .netrc files outside of home directories have no meaning and are not subject to this rule If the ~/.rhosts or ~/.shosts are not owned by the owner of the home directory where they are immediately located or by root, this is a finding. | Ensure the permission for these files is set to 600 or more restrictive and their owner is root or the same as the owner of the home directory in which they reside. Procedure: # chmod 600 /etc/hosts.equiv # chmod 600 /etc/ssh/shosts.equiv # chown root /etc/hosts.equiv # chown root /etc/ssh/shosts.equiv # find / -name .rhosts # chmod 600 /<home directory>/.rhosts # chown <home directory owner> <home directory>/.rhosts # find / -name .shosts # chmod 600 <directory location>/.shosts # chown <home directory owner> <home directory>/.shosts # find / -name .netrc # chmod 600 <directory location>/.netrc # chown <home directory owner> <home directory>/.netrc |
| V-4430 | CCI-000225 | medium | The cron.deny file must be owned by root, bin, or sys. | Cron daemon control files restrict the scheduling of automated tasks and must be protected. | # ls -lL /etc/cron.deny If the cron.deny file is not owned by root, sys, or bin, this is a finding. | # chown root /etc/cron.deny |
| V-4687 | CCI-000068 | high | The rsh daemon must not be running. | The rshd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service. | Check to see if rshd is configured to run on startup. Procedure: # grep disable /etc/xinetd.d/rsh If /etc/xinetd.d/rsh exists and rsh is found to be enabled, this is a finding. | Edit /etc/xinetd.d/rsh and set "disable=yes". |
| V-4688 | CCI-001435 | high | The rexec daemon must not be running. | The rexecd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service. | # grep disable /etc/xinetd.d/rexec If the service file exists and is not disabled, this is a finding. | Edit /etc/xinetd.d/rexec and set "disable=yes" |
| V-4689 | CCI-001230 | high | The SMTP service must be an up-to-date version. | The SMTP service version on the system must be current to avoid exposing vulnerabilities present in unpatched versions. | Determine the version of the SMTP service software. Procedure: #rpm -q sendmail RedHat sendmail 8.13.8-8 is the latest required version. If the RedHat sendmail is installed and the version is not at least 8.13.8-8, this is a finding. #rpm -q postfix RedHat postfix-2.5.1-0.4.rhel5 is the latest required version. If the postfix is installed and the version is not at least 2-5.1-0.4, this is a finding. | Obtain and install a newer version of the SMTP service software (sendmail or Postfix) from RedHat. |
| V-4690 | CCI-000366 | high | The sendmail server must have the debug feature disabled. | Debug mode is a feature present in older versions of sendmail which, if not disabled, may allow an attacker to gain access to a system through the sendmail service. | Check for an enabled "debug" command provided by the SMTP service. Procedure: # telnet localhost 25 debug If the command does not return a 500 error code of "command unrecognized" or a 550 error code of "access denied", this is a finding. The RHEL distribution ships with sendmail Version 8.13.8 which is not vulnerable. This should never be a finding. | Obtain and install a newer version of the SMTP service software (sendmail or Postfix) from RedHat. |
| V-4691 | CCI-001230 | high | The SMTP service must not have a uudecode alias active. | A common configuration for older Mail Transfer Agents (MTAs) is to include an alias for the decode user. All mail sent to this user is sent to the uudecode program, which automatically converts and stores files. By sending mail to the decode or the uudecode aliases present on some systems, a remote attacker may be able to create or overwrite files on the remote host. This could possibly be used to gain remote access. | Check the SMTP service for an active "decode" command. Procedure: # telnet localhost 25 decode If the command does not return a 500 error code of "command unrecognized", this is a finding. | Disable mail aliases for decode and uudecode. If the /etc/aliases or /usr/lib/aliases (mail alias) file contains entries for these programs, remove them or disable them by placing "#" at the beginning of the line, and then executing the new aliases command. For more information on mail aliases, refer to the man page for aliases. Disabled aliases would be similar to these examples: # decode: |/usr/bin/uudecode # uudecode: |/usr/bin/uuencode -d |
| V-4692 | CCI-000366 | low | The SMTP service must not have the EXPN feature active. | The SMTP EXPN function allows an attacker to determine if an account exists on a system, providing significant assistance to a brute force attack on user accounts. EXPN may also provide additional information concerning users on the system, such as the full names of account owners. | This vulnerability is applicable only to sendmail. If Postfix is the SMTP service for the system this will never be a finding. Procedure: Determine if EXPN is disabled. # grep -v "^#" /etc/mail/sendmail.cf |grep -i PrivacyOptions If nothing is returned or the returned line does not contain "noexpn", this is a finding. | Rebuild /etc/mail/sendmail.cf with the "noexpn" Privacy Flag set. Procedure: Edit /etc/mail/sendmail.mc resetting the Privacy Flags to the default: define('confPRIVACYFLAGS', 'authwarnings,novrfy,noexpn,restrictqrun')dnl Rebuild the sendmail.cf file with: # make -C /etc/mail Restart the sendmail service. # service sendmail restart |
| V-4693 | CCI-000366 | low | The SMTP service must not have the Verify (VRFY) feature active. | The VRFY command allows an attacker to determine if an account exists on a system, providing significant assistance to a brute force attack on user accounts. VRFY may provide additional information about users on the system, such as the full names of account owners. | Determine if VRFY is disabled. Procedure: # telnet localhost 25 vrfy root If the command does not return a 500 error code of "command unrecognized", this is a finding. or: # grep -v "^#" /etc/mail/sendmail.cf |grep -i vrfy Verify the VRFY command is disabled with an entry in the sendmail.cf file. The entry could be any one of "Opnovrfy", "novrfy", or "goaway", which could also have other options included, such as "noexpn". The "goaway" argument encompasses many things, such as "novrfy" and "noexpn". If no setting to disable VRFY is found, this is a finding. | Add the "novrfy" flag to your sendmail in /etc/mail/sendmail.cf. Procedure: Edit the definition of "confPRIVACY_FLAGS" in /etc/mail/sendmail.mc to include "novrfy". Rebuild the sendmail.cf file with: # make -C /etc/mail Restart the sendmail service. # service sendmail restart |
| V-4694 | CCI-000366 | low | The sendmail service must not have the wizard backdoor active. | Very old installations of the Sendmail mailing system contained a feature whereby a remote user connecting to the SMTP port can enter the WIZ command and be given an interactive shell with root privileges. | Log into the sendmail server with telnet and test the "wiz" commmand" Procedure: # telnet localhost 25 Trying 127.0.0.1... Connected to locahost.localdomain (127.0.0.1). Escape character ... Once the telnet greeting is complete type: wiz If you do not get a "Command unrecognized: " message, this is a finding. | If the WIZ command exists on sendmail then the version of sendmail is archaic and should be replaced with the latest version from RedHat. WIZ is not available on any sendmail distrubution of RHEL. However,If the WIZ command is enabled on sendmail, it should be disabled by adding this line to the sendmail.cf configuration file (note that it must be typed in uppercase): OW* For the change to take effect, kill the sendmail process, refreeze the sendmail.cf file, and restart the sendmail process. |
| V-4695 | CCI-000225 | high | Any active TFTP daemon must be authorized and approved in the system accreditation package. | TFTP is a file transfer protocol often used by embedded systems to obtain configuration data or software. The service is unencrypted and does not require authentication of requests. Data available using this service may be subject to unauthorized access or interception. | Determine if the TFTP daemon is active. # chkconfig --list | grep tftp If TFTP is found enabled ("on") and not documented using site-defined procedures, it is a finding. | Document or Disable the TFTP daemon. If the TFTP daemon is necessary on the system, document and justify its usage for approval from the IAO. If the TFTP daemon is not necessary on the system, turn it off. # chkconfig tftp off # service xinetd restart |
| V-4696 | CCI-001436 | medium | The system must not have the UUCP service active. | The UUCP utility is designed to assist in transferring files, executing remote commands, and sending e-mail between UNIX systems over phone lines and direct connections between systems. The UUCP utility is a primitive and arcane system with many security issues. There are alternate data transfer utilities/products that can be configured to more securely transfer data by providing for authentication as well as encryption. | # service uucp status if UUCP is "running", this is a finding. | # chkconfig uucp off # service uucp stop # service xinetd restart |
| V-4697 | CCI-000225 | high | X displays must not be exported to the world. | Open X displays allow an attacker to capture keystrokes and to execute commands remotely. Many users have their X Server set to “xhost +â€, permitting access to the X Server by anyone, from anywhere. | If Xwindows is not used on the system, this is not applicable. Check the output of the "xhost" command from an X terminal. Procedure: # xhost If the output reports access control is enabled (and possibly lists the hosts able to receive X window logins), this is not a finding. If the xhost command returns a line indicating access control is disabled, this is a finding. Note: It may be necessary to define the display if the command reports it cannot open the display. Procedure: $ DISPLAY=MachineName:0.0; export DISPLAY MachineName may be replaced with an Internet Protocol Address. Repeat the check procedure after setting the display. | If using an xhost-type authentication the "xhost -" command can be used to remove current trusted hosts and then selectively allow only trusted hosts to connect with "xhost +" commands. A cryptographically secure authentication, such as provided by the xauth program, is always preferred. Refer to your X11 server's documentation for further security information. |
| V-4701 | CCI-001551 | low | The system must not have the finger service active. | The finger service provides information about the system's users to network clients. This information could expose more information for potential used in subsequent attacks. | # grep disable /etc/xinetd.d/finger If the finger service is not disabled, this is a finding. | Edit /etc/xinetd.d/finger and set "disable=yes" |
| V-4702 | CCI-000787 | medium | If the system is an anonymous FTP server, it must be isolated to the DMZ network. | Anonymous FTP is a public data service which is only permitted in a server capacity when located on the DMZ network. | Use the command "ftp" to connect the system's FTP service. Attempt to log into this host with a user name of anonymous and a password of guest (also try the password of guest@mail.com). If the logon is not successful, this check is Not Applicable. Ask the SA if the system is located on a DMZ network. If the system is not located on a DMZ network, this is a finding. | Remove anonymous ftp capability or move the system to a DMZ network. |
| V-11940 | CCI-001230 | high | The operating system must be a supported release. | An operating system release is considered "supported" if the vendor continues to provide security patches for the product. With an unsupported release, it will not be possible to resolve security issues discovered in the system software. | Check the version of the operating system. Example: # cat /etc/redhat-release Vendor End-of-Support Information: Red Hat Enterprise 5: 31 Mar 2014 Check with the vendor for additional information. If the version installed is not supported, this is a finding. | Upgrade to a supported version of the operating system. |
| V-11945 | CCI-001069 | medium | A file integrity tool must be used at least weekly to check for unauthorized file changes, particularly the addition of unauthorized system libraries or binaries, or for unauthorized modification to authorized system libraries or binaries. | Changes in system libraries, binaries and other critical system files can indicate compromise or significant system events such as patching needing to be checked by automated processes and the results reviewed by the SA. NOTE: For MAC I systems, increase the frequency to daily. | Determine if there is an automated job, scheduled to run weekly or more frequently, to run the file integrity tool to check for unauthorized additions to system libraries. The check can be done using Advanced Intrusion Detection Environment (AIDE) which is part of the Red Hat Enterprise Linux (RHEL) distribution. Other file integrity software may be used but must be checked manually. Procedure: Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/* for the presence of an "aide" job to run at least weekly, which should have asterisks (*) in columns 3, 4, and 5. Check the weekly cron directory (/etc/cron.weekly) for any script running "aide --check" or "aide -C" or simply "aide". If there is not, this is a finding. NOTE: For MAC I systems, increase the frequency to daily. | Establish an automated job, scheduled to run weekly or more frequently, to run "aide --check" which is the file integrity tool to check for unauthorized system libraries or binaries. NOTE: For MAC I systems, increase the frequency to daily. |
| V-11946 | CCI-000366 | medium | UIDs reserved for system accounts must not be assigned to non-system accounts. | Reserved UIDs are typically used by system software packages. If non-system accounts have UIDs in this range, they may conflict with system software, possibly leading to the user having permissions to modify system files. | Check the UID assignments for all accounts. # cut -d: -f 1,3 /etc/passwd | egrep ":[1-4][0-9]{2}$|:[0-9]{1,2}$" Confirm all accounts with a UID of 499 and below are used by a system account. If a UID reserved for system accounts (0 - 499) is used by a non-system account, then this is a finding. | Change the UID numbers for non-system accounts with reserved UIDs (those less or equal to 499). |
| V-11947 | CCI-000205 | medium | The system must require passwords contain a minimum of 14 characters. | The use of longer passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques by increasing the password search space. | Check the system password length setting. Procedure: Check the password minlen option # grep pam_cracklib.so /etc/pam.d/system-auth Confirm the minlen option is set to at least 14 as in the example below: password required pam_cracklib.so minlen=14 There may be other options on the line. If no such line is found, or the minlen is less than 14 this is a finding. | Edit "/etc/pam.d/system-auth" to include the line: password required pam_cracklib.so minlen=14 prior to the "password include system-auth-ac" line. |
| V-11948 | CCI-000192 | medium | The system must require passwords contain at least one uppercase alphabetic character. | To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use. | Check the ucredit setting. # grep ucredit /etc/pam.d/system-auth If ucredit is not set to -1, this is a finding. | Edit "/etc/pam.d/system-auth" to include the line: password required pam_cracklib.so ucredit=-1 prior to the "password include system-auth-ac" line. |
| V-11972 | CCI-000194 | medium | The system must require passwords contain at least one numeric character. | To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use. | Check the dcredit setting. Procedure: Check the password dcredit option # grep pam_cracklib.so /etc/pam.d/system-auth Confirm the dcredit option is set to -1 as in the example: password required pam_cracklib.so dcredit=-1 There may be other options on the line. If no such line is found, or the dcredit option is not -1 this is a finding. | Edit "/etc/pam.d/system-auth" to include the line: password required pam_cracklib.so dcredit=-1 prior to the "password include system-auth-ac" line. |
| V-11973 | CCI-001619 | medium | The system must require passwords contain at least one special character. | To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use. | Check the ocredit setting. Procedure: Check the password ocredit option # grep pam_cracklib.so /etc/pam.d/system-auth Confirm the ocredit option is set to -1 as in the example: password required pam_cracklib.so ocredit=-1 There may be other options on the line. If no such line is found, or the ocredit is not -1 this is a finding. | Edit "/etc/pam.d/system-auth" to include the line: password required pam_cracklib.so ocredit=-1 prior to the "password include system-auth-ac" line. |
| V-11975 | CCI-000366 | medium | The system must require passwords contain no more than three consecutive repeating characters. | To enforce the use of complex passwords, the number of consecutive repeating characters is limited. Passwords with excessive repeated characters may be more vulnerable to password-guessing attacks. | Check the maxrepeat setting. Procedure: Check the password maxrepeat configuration # grep pam_cracklib.so /etc/pam.d/system-auth If the maxrepeat option is missing, this is a finding. If the maxrepeat option is set to more than 3, this is a finding. | Edit "/etc/pam.d/system-auth" to include the line: password required pam_cracklib.so maxrepeat=3 prior to the "password include system-auth-ac" line. |
| V-11976 | CCI-000180 | medium | User passwords must be changed at least every 60 days. | Limiting the lifespan of authenticators limits the period of time an unauthorized user has access to the system while using compromised credentials and reduces the period of time available for password-guessing attacks to run against a single password. | Check the max days field (the 5th field) of /etc/shadow. # more /etc/shadow If the max days field is equal to 0 or greater than 60 for any user, this is a finding. | Set the max days field to 60 for all user accounts. # passwd -x 60 <user> |
| V-11977 | CCI-000199 | medium | All non-interactive/automated processing account passwords must be changed at least once per year or be locked. | Limiting the lifespan of authenticators limits the period of time an unauthorized user has access to the system while using compromised credentials and reduces the period of time available for password-guessing attacks to run against a single password. Locking the password for non-interactive and automated processing accounts is preferred as it removes the possibility of accessing the account by a password. On some systems, locking the passwords of these accounts may prevent the account from functioning properly. Passwords for non-interactive/automated processing accounts must not be used for direct logon to the system. | Ask the SA if there are any automated processing accounts on the system. If there are automated processing accounts on the system, ask the SA if the passwords for those automated accounts are changed at least once a year or are locked. If SA indicates passwords for automated processing accounts are not changed once per year or are not locked, this is a finding. | Implement or establish procedures to change the passwords of automated processing accounts at least once per year or lock them. |
| V-11979 | CCI-000770 | medium | The root account must not be used for direct log in. | Direct login with the root account prevents individual user accountability. Acceptable non-routine uses of the root account for direct login are limited to emergency maintenance, the use of single-user mode for maintenance, and situations where individual administrator accounts are not available. | Check if root is used for direct logins. Procedure: # last root | grep -v reboot If any direct login records for root are listed, this is a finding. | Enforce policy requiring all root account access is attained by first logging into a user account and then becoming root preferably through the use of "sudo" which provides traceability to the command level. If that is not workable then using "su" to access the root account will provide traceability to the login user. |
| V-11980 | CCI-000126 | medium | The system must log successful and unsuccessful access to the root account. | If successful and unsuccessful logins and logouts are not monitored or recorded, access attempts cannot be tracked. Without this logging, it may be impossible to track unauthorized access to the system. | Check the log files to determine if access to the root account is being logged. Procedure: Examine /etc/syslog.conf to confirm the location to which "authpriv" messages will be directed. The default syslog.conf uses /var/log/messages and /var/log/secure but this needs to be confirmed. # grep @ /etc/syslog.conf If a line starting with "*.*" is returned then all syslog messages will be sent to system whose address appears after the "@". In this case syslog may or may not be configured to also log "authpriv" messages locally. # grep authpriv /etc/syslog.conf If any lines are returned which do not start with "#" the "authpriv" messages will be sent to the indicated files or remote systems. Try to "su -" and enter an incorrect password. If there are no records indicating the authentication failure, this is a finding. | Troubleshoot the system logging configuration to provide for logging of root account login attempts. Procedure: Edit /etc/syslog.conf to make sure "authpriv.*" messages are directed to a file or remote system. Examine /etc/audit/audit.rules to ensure user authentication messages have not been specifically excluded. There remove any entries that correspond to: -a exclude,never -Fmsgtype=USER_START -a exclude,never -Fmsgtype=USER_LOGIN -a exclude,never -Fmsgtype=USER_AUTH -a exclude,never -Fmsgtype=USER_END -a exclude,never -Fmsgtype=USER_ACCT |
| V-11981 | CCI-000225 | medium | All global initialization files must have mode 0644 or less permissive. | Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. | Check global initialization files permissions: # ls -l /etc/bashrc # ls -l /etc/csh.cshrc # ls -l /etc/csh.login # ls -l /etc/csh.logout # ls -l /etc/environment # ls -l /etc/ksh.kshrc # ls -l /etc/profile # ls -l /etc/suid_profile # ls -l /etc/profile.d/* If global initialization files are more permissive than 0644, this is a finding. | Change the mode of the global initialization file(s) to 0644. # chmod 0644 <global initialization file> |
| V-11982 | CCI-000225 | medium | All global initialization files must be owned by root. | Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture. | Check the ownership of global initialization files. Procedure: # ls -lL etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* This should show information for each file. Examine to ensure the owner is always root or: # ls etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|xargs stat -L -c %U:%n|egrep -v "^root" This will show you only the owner and filename of files not owned by root. If any global initialization file is not owned by root, this is a finding. | Change the ownership of global initialization files with incorrect ownership. Procedure: # chown root <global initialization files> or: # ls etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|xargs stat -L -c %U:%n|egrep -v "^root"|cut -d: -f2|xargs chown root will set the owner of all files not currently owned by root to root. |
| V-11983 | CCI-000225 | medium | All global initialization files must be group-owned by root, sys, bin, other, system, or the system default. | Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture. | Check the group ownership of global initialization files. Procedure: # ls -lL etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* This should show information for each file. Examine to ensure the group is always root or: # ls -lL etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|sed "s/^[^\/]*//"|xargs stat -L -c %G:%n|egrep -v "^(root|sys|bin|other):" will show you only the group and filename of files not owned by one of the approved groups. If any global initialization file is not group-owned by root, sys, bin, other, system, or the system default, this is a finding. | Change the group ownership of the global initialization file(s) with incorrect group ownership. Procedure: # chgrp root <global initialization file> or: # ls -lL /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|sed "s/^[^\/]*//"|xargs stat -L -c %G:%n|egrep -v "^(root|sys|bin|other):"|cut -d: -f2|xargs chgrp root will set the group of all files not currently owned by an approved group to root. |
| V-11984 | CCI-000225 | medium | All skeleton files and directories (typically in /etc/skel) must be owned by root or bin. | If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files. Failure to give ownership of sensitive files or utilities to root or bin provides the designated owner and unauthorized users with the potential to access sensitive information or change the system configuration which could weaken the system's security posture. | Check skeleton files ownership. # ls -alL /etc/skel If a skeleton file is not owned by root or bin, this is a finding. | Change the ownership of skeleton files with incorrect mode: # chown root <skeleton file> or # ls -L /etc/skel|xargs stat -L -c %U:%n|egrep -v "^(root|bin):"|cut -d: -f2|chown root will change all files not owned by root or bin to root. |
| V-11985 | CCI-000366 | medium | All global initialization files' executable search paths must contain only absolute paths. | The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths. | Check the global initialization files' executable search paths. Procedure: # grep PATH /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/) this is a relative path, this is a finding. | Edit the global initialization file(s) with PATH variables containing relative paths. Edit the file and remove the relative path from the PATH variable. |
| V-11986 | CCI-000366 | medium | All local initialization files' executable search paths must contain only absolute paths. | The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory or other relative paths, executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths. | Verify local initialization files have executable search path containing only absolute paths or relative paths are necessary and documented. Procedure: # cut -d: -f6 /etc/passwd |xargs -n1 -IDIR find DIR -name ".*" -type f -maxdepth 1 -exec grep -l PATH {} \; This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/) this is a relative path, ask the SA or IAt if the relative path is required for the operation of a specific application. If it is not then this is a finding. finding. | Edit the local initialization file and remove the relative path entry from the executable search path variable. If this is not feasable, justify and document the necessity of having the relative path for a specific application. |
| V-11987 | CCI-000366 | medium | The .rhosts, .shosts, hosts.equiv, shosts.equiv, /etc/passwd, /etc/shadow, and/or /etc/group files must not contain a plus (+) without defining entries for NIS+ netgroups. | A plus (+) in system accounts files causes the system to lookup the specified entry using NIS. If the system is not using NIS, no such entries should exist. | Check system configuration files for plus (+) entries. Procedure: # find / -name .rhosts # grep + /<directorylocation>/.rhosts # find / -name .shosts # grep + /<directorylocation>/.shosts # find / -name hosts.equiv # grep + /<directorylocation>/hosts.equiv # find / -name shosts.equiv # grep + /<directorylocation>/shosts.equiv # grep + /etc/passwd # grep + /etc/shadow # grep + /etc/group If the .rhosts, .shosts, hosts.equiv, shosts.equiv, /etc/passwd, /etc/shadow, and/or /etc/group files contain a plus (+) and do not define entries for NIS+ netgroups, this is a finding. | Edit the .rhosts, .shosts, hosts.equiv, shosts.equiv, /etc/passwd, /etc/shadow, and/or /etc/group files and remove entries containing a plus (+). |
| V-11988 | CCI-000366 | high | There must be no .rhosts, .shosts, hosts.equiv, or shosts.equiv files on the system. | The .rhosts, .shosts, hosts.equiv, and shosts.equiv files are used to configure host-based authentication for individual users or the system. Host-based authentication is not sufficient for preventing unauthorized access to the system. | Check for the existence of the files. # find / -name .rhosts # find / -name .shosts # find / -name hosts.equiv # find / -name shosts.equiv If .rhosts, .shosts, hosts.equiv, or shosts.equiv are found and their use has not been documented and approved by the IAO, this is a finding. | Remove all the r-commands access control files. Procedure: # find / -name .rhosts -exec rm {} \; # find / -name .shosts -exec rm {} \; # find / -name hosts.equiv -exec rm {} \; # find / -name shosts.equiv -exec rm {} \; |
| V-11989 | CCI-000366 | medium | The .rhosts file must not be supported in PAM. | .rhosts files are used to specify a list of hosts permitted remote access to a particular account without authenticating. The use of such a mechanism defeats strong identification and authentication requirements. | Check the PAM configuration for rhosts_auth. Example: # grep rhosts_auth /etc/pam.d/* If a rhosts_auth entry is found, this is a finding. | Edit the file(s) in /etc/pam.d referencing the rhosts_auth module, and remove the references to the rhosts_auth module. |
| V-11990 | CCI-000225 | medium | All public directories must be group-owned by root, sys, bin, or an application group. | If a public directory has the sticky bit set and is not group-owned by a privileged GID, unauthorized users may be able to modify files created by others. The only authorized public directories are those temporary directories supplied with the system or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system and by users for temporary file storage, (e.g., /tmp), and for directories requiring global read/write access. | Check the group-ownership of public directories. Procedure: # find / -type d -perm -1002 -exec ls -ld {} \; If any public directory is not group-owned by root, sys, bin, or an application group, this is a finding. | Change the group-ownership of the public directory. Procedure: # chgrp root /tmp (Replace root with a different system group and/or /tmp with a different public directory as necessary.) |
| V-11994 | CCI-000225 | medium | Crontabs must be owned by root or the crontab creator. | To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured. | List all crontabs on the system. # ls -lL /var/spool/cron # ls -lL /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls -lL /etc/cron*|grep -v deny If any crontab is not owned by root or the creating user, this is a finding. | Change the crontab owner to root or the crontab creator. # chown root <crontab file> or # chown <user> <crontab file> |
| V-11995 | CCI-000225 | medium | Default system accounts (with the exception of root) must not be listed in the cron.allow file or must be included in the cron.deny file, if cron.allow does not exist. | To centralize the management of privileged account crontabs, of the default system accounts, only root may have a crontab. | Check the cron.allow and cron.deny files for the system. # more /etc/cron.allow # more /etc/cron.deny If a default system account (such as bin, sys, adm, or others, traditionally UID less than 500) is listed in the cron.allow file, or not listed in the cron.deny file and if no cron.allow file exists, this is a finding. | Remove default system accounts (such as bin, sys, adm, or others, traditionally UID less than 500) from the cron.allow file if it exists, or add those accounts to the cron.deny file. |
| V-11996 | CCI-000366 | low | Process core dumps must be disabled unless needed. | Process core dumps contain the memory in use by the process when it crashed. Process core dump files can be of significant size and their use can result in file systems filling to capacity, which may result in Denial of Service. Process core dumps can be useful for software debugging. | # ulimit -c If the above command does not return 0 and the enabling of core dumps has not been documented and approved by the IAO, this a finding. | Edit /etc/security/limits.conf and set a hard limit for "core" to 0 for all users. |
| V-11997 | CCI-000225 | low | The kernel core dump data directory must be owned by root. | Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the kernel core dump data directory is not owned by root, the core dumps contained in the directory may be subject to unauthorized access. | Check the ownership of the kernel core dump data directory. # ls -ld /var/crash If the kernel core dump data directory is not owned by root, this is a finding. | Change the owner of the kernel core dump data directory to root. # chown root /var/crash |
| V-11999 | CCI-000366 | medium | The system must implement non-executable program stacks. | A common type of exploit is the stack buffer overflow. An application receives, from an attacker, more data than it is prepared for and stores this information on its stack, writing beyond the space reserved for it. This can be designed to cause execution of the data written on the stack. One mechanism to mitigate this vulnerability is for the system to not allow the execution of instructions in sections of memory identified as part of the stack. | Verify "exec_shield" and "randomize_va_space" have not been changed from the default "1" settings. Procedure: #sysctl kernel.exec-shield If the return value is not: kernel.exec-shield = 1 this is a finding. #sysctl kernel.randomize_va_space If the return value is not: kernel.randomize_va_space = 1 this is a finding. | Examine /etc/sysctl.conf for "kernel.exec-shield" and "kernel.randomize_va_space" entries and if found remove them. The system default of "1" enables these modules. |
| V-12002 | CCI-001551 | medium | The system must not forward IPv4 source-routed packets. | Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router. | Verify the system does not accept source-routed IPv4 packets. Procedure: # grep [01] /proc/sys/net/ipv4/conf/*/accept_source_route|egrep "default|all" If all of the returned lines do not end with 0, this is a finding. Note: The same setting is used by Linux for both the local acceptance and forwarding of source-routed IPv4 packets. | Configure the system to not accept source-routed IPv4 packets. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.accept_source_route=0" and "net.ipv4.conf.default.accept_source_route=0". Reload the sysctls. Procedure: # sysctl -p |
| V-12003 | CCI-001208 | low | A separate file system must be used for user home directories (such as /home or an equivalent). | The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing. | Determine if the /home path is a separate filesystem. # grep "/home " /etc/fstab If no result is returned, /home is not on a separate filesystem this is a finding. | Migrate the /home (or equivalent) path onto a separate file system. |
| V-12004 | CCI-000126 | medium | The system must log informational authentication data. | Monitoring and recording successful and unsuccessful logins assists in tracking unauthorized access to the system. | Check /etc/syslog.conf and verify the authpriv facility is logging both the "notice" and "info" priority messages. Procedure: For a given action all messages of a higher severity or "priority" are logged. The three lowest priorities in ascending order are "debug","info" and "notice". A priority of "info" will include "notice". A priority of "debug" includes both "info" and "notice". Enter/Input: # grep "authpriv.debug" /etc/syslog.conf # grep "authpriv.info" /etc/syslog.conf # grep "authpriv\.\*" /etc/syslog.conf If an "authpriv.*", "authpriv.debug", or "authpriv.info" entry is not found, this is a finding. | Edit /etc/syslog.conf and add local log destinations for "authpriv.*", "authpriv.debug" or "authpriv.info". |
| V-12005 | CCI-000305 | medium | Inetd and xinetd must be disabled or removed if no network services utilizing them are enabled. | Unnecessary services should be disabled to decrease the attack surface of the system. | # ps -ef |grep xinetd If xinetd is not running, this check is not a finding. # grep -v "^#" /etc/xinetd.conf # grep disable /etc/xinetd.d/* |grep no If no active services are found, and the inetd daemon is running, this is a finding. | # service xinetd stop ; chkconfig xinetd off |
| V-12006 | CCI-000366 | medium | The SMTP service HELP command must not be enabled. | The HELP command should be disabled to mask version information. The version of the SMTP service software could be used by attackers to target vulnerabilities present in specific software versions. | Check if Help is disabled. This rule is for "sendmail" only and not applicable to "Postfix". Procedure: # telnet localhost 25 > help If the help command returns any sendmail version information, this is a finding. | To disable the SMTP HELP command, remove /etc/mail/helpfile. |
| V-12010 | CCI-000366 | medium | Unencrypted FTP must not be used on the system. | : FTP is typically unencrypted and presents confidentiality and integrity risks. FTP may be protected by encryption in certain cases, such as when used in a Kerberos environment. SFTP and FTPS are encrypted alternatives to FTP. | Perform the following to determine if unencrypted FTP is enabled: # chkconfig --list gssftp # chkconfig --list vsftpd If any of these services are found, ask the SA if these services are encrypted. If they are not, this is a finding. | Disable the FTP daemons. Procedure: # chkconfig gssftp off # chkconfig vsftpd off |
| V-12011 | CCI-000225 | medium | All FTP users must have a default umask of 077. | The umask controls the default access mode assigned to newly created files. An umask of 077 limits new files to mode 700 or less permissive. Although umask is stored as a 4-digit number, the first digit representing special access modes is typically ignored or required to be zero (0). | Check the umask setting for FTP users. Procedure: For gssftp: Assuming an anonymous ftp user has been defined with no user initialization script invoked to change the umask # ftp localhost Name: (localhost:root): anonymous Password: anything ftp>umask If the umask value returned is not 077, this is a finding. or: # grep "server_args" /etc/xinetd.d/gssftp The default umask for FTP is "023" if the server _args entry does not contain "-u 077" this is a finding. For vsftp: # grep "_mask" /etc/vsftpd/vsftpd.conf The default "local_umask" setting is 077. If this has been changed, or the "anon_umask" setting is not 077, this is a finding. | Edit the initialization files for the ftp user and set the umask to 077. Procedure: For gssftp: Modify the /etc/xinetd.d/gssftp file adding "-u 077" to the server_args entry. For vsftp: Modify the "/etc/vsftpd/vsftpd.conf" setting "local_umask" and "anon_umask" to 077. |
| V-12014 | CCI-000225 | medium | All .Xauthority files must have mode 0600 or less permissive. | .Xauthority files ensure the user is authorized to access specific X Windows host. Excessive permissions may permit unauthorized modification of these files, which could lead to Denial of Service to authorized access or allow unauthorized access to be obtained. | Check the file permissions for the .Xauthority files. Procedure: # ls -la |egrep "(\.Xauthority|\.xauth)" If the file mode is more permissive than 0600, this is finding. | Change the mode of the .Xauthority files. Procedure: # chmod 0600 .Xauthority |
| V-12016 | CCI-000297 | medium | .Xauthority or X*.hosts (or equivalent) file(s) must be used to restrict access to the X server. | If access to the X server is not restricted, a user's X session may be compromised. | Determine if the X server is running. Procedure: # ps -ef |grep X Determine if xauth is being used. Procedure: # xauth xauth> list If the above command sequence does not show any host other than the localhost, then xauth is not being used. Search the system for an X*.hosts file, where "*" is a display number used to limit X window connections. If no files are found, X*.hosts files are not being used. If the X*.hosts files contain any unauthorized hosts, this is a finding. If both xauth and X*.hosts files are not being used, this is a finding. | Create an X*.hosts file, where "*" is a display number used to limit X window connections. Add the list of authorized X clients to the file. |
| V-12017 | CCI-000225 | medium | The .Xauthority utility must only permit access to authorized hosts. | If unauthorized clients are permitted access to the X server, a user's X session may be compromised. | Check the X window system access is limited to authorized clients. Procedure: # xauth xauth> list Ask the SA if the clients listed are authorized. If any are not, this is a finding. | Remove unauthorized clients from the xauth configuration. # xauth remove <display name> |
| V-12018 | CCI-001436 | medium | X Window System connections not required must be disabled. | If unauthorized clients are permitted access to the X server, a user's X session may be compromised. | Determine if the X window system is running. Procedure: # ps -ef |grep Xorg Ask the SA if the X window system is an operational requirement. If it is not, this is a finding. | Disable the X Windows server on the system. |
| V-12019 | CCI-000225 | medium | The snmpd.conf file must be owned by root. | The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification. If the file is not owned by root, it may be subject to access and modification from unauthorized users. | Determine the owner of the SNMP configuration file. Procedure: Find the snmpd.conf file. The default install location is /etc/snmp/snmpd.conf but may be different depending on the SNMP agent installed. # find / -name snmpd.conf # ls -lL <snmpd.conf> If the snmpd.conf file is not owned by root, this is a finding. | Change the owner of the snmpd.conf file to root. Procedure: # chown root <snmpd.conf file> |
| V-12020 | CCI-000366 | medium | The system must not be used as a syslog server (loghost) for systems external to the enclave. | Syslog messages are typically unencrypted, may contain sensitive information, and are restricted to the enclave. | Ask the SA if the loghost server is collecting data for hosts outside the local enclave. If it is, this is a finding. | Configure the hosts outside of the local enclave to not log to this system. |
| V-12021 | CCI-000366 | medium | The syslog daemon must not accept remote messages unless it is a syslog server documented using site-defined procedures. | Unintentionally running a syslog server accepting remote messages puts the system at increased risk. Malicious syslog messages sent to the server could exploit vulnerabilities in the server software itself, could introduce misleading information in to the system's logs, or could fill the system's storage leading to a Denial of Service. | Ask the SA if the system is an authorized syslog server. If the system is an authorized syslog server, this is not applicable. Determine if the system's syslog service is configured to accept remote messages. # ps -ef | grep syslogd If the '-r' option is present, the system is configured to accept remote syslog messages, and this is a finding. | Edit /etc/sysconfig/syslog to removing the '-r' in SYSLOGD_OPTIONS. Restart the syslogd service. |
| V-12022 | CCI-000366 | medium | The SSH daemon must be configured for IP filtering. | The SSH daemon must be configured for IP filtering to provide a layered defense against connection attempts from unauthorized addresses. | Check the TCP wrappers configuration files to determine if sshd is configured to use TCP wrappers. Procedure: # grep sshd /etc/hosts.deny # grep sshd /etc/hosts.allow If no entries are returned, the TCP wrappers are not configured for sshd, this is a finding. | Add appropriate IP restrictions for SSH to the /etc/hosts.deny and/or /etc/hosts.allow files. |
| V-12023 | CCI-000366 | medium | IP forwarding for IPv4 must not be enabled, unless the system is a router. | If the system is configured for IP forwarding and is not a designated router, it could be used to bypass network security by providing a path for communication not filtered by network devices. | Check if the system is configured for IPv4 forwarding. If the system is a VM host and acts as a router solely for the benefits of its client systems, then this rule is not applicable. Procedure: # cat /proc/sys/net/ipv4/ip_forward If the value is set to "1", IPv4 forwarding is enabled this is a finding. | Edit "/etc/sysctl.conf" and set net.ipv4.ip_forward to "0". Restart the system or run "sysctl -p" to make the change take effect. |
| V-12024 | CCI-000366 | medium | The system must not have a public Instant Messaging (IM) client installed. | Public (IM) systems are not approved for use and may result in the unauthorized distribution of information. IM clients provide a way for a user to send a message to one or more other users in real time. Additional capabilities may include file transfer and support for distributed game playing. Communication between clients and associated directory services are managed through messaging servers. Commercial IM clients include AOL Instant Messenger (AIM), MSN Messenger, and Yahoo! Messenger. IM clients present a security issue when the clients route messages through public servers. The obvious implication is potentially sensitive information could be intercepted or altered in the course of transmission. This same issue is associated with the use of public e-mail servers. In order to reduce the potential for disclosure of sensitive Government information and to ensure the validity of official government information, IM clients connecting to public IM services will not be installed. Clients use to access internal or DoD-controlled IM services are permitted. | If an IM client is installed, ask the SA if it has access to any public domain IM servers. If it does have access to public servers, this is a finding. | Uninstall the IM client from the system, or configure the client to only connect to DoD-approved IM services. |
| V-12025 | CCI-001436 | medium | The system must not have any peer-to-peer file-sharing application installed. | Peer-to-peer file-sharing software can result in the unintentional exfiltration of information. There are also many legal issues associated with these types of utilities including copyright infringement or other intellectual property issues. The ASD Memo "Use of Peer-to-Peer (P2P) File-Sharing Applications across the DoD" states the following: “P2P file-sharing applications are authorized for use on DOD networks with approval by the appropriate Designated Approval Authority (DAA). Documented requirements, security architecture, configuration management process, and a training program for users are all requirements within the approval process. The unauthorized use of application or services, including P2P applications, is prohibited, and such applications or services must be eliminated.†P2P applications include, but are not limited to, the following: -Napster -Kazaa -ARES -Limewire -IRC Chat Relay -BitTorrent | Ask the SA if any peer-to-peer file-sharing applications are installed. Some examples of these applications include: - Napster - Kazaa - ARES - Limewire - IRC Chat Relay - BitTorrent If any of these applications are installed, this is a finding. | Uninstall the peer-to-peer file sharing application(s) from the system. |
| V-12026 | CCI-000366 | medium | NIS maps must be protected through hard-to-guess domain names. | The use of hard-to-guess NIS domain names provides additional protection from unauthorized access to the NIS directory information. | Check the domain name for NIS maps. Procedure: # domainname If the name returned is simple to guess, such as the organization name, building or room name, etc., this is a finding. If the system does not use NIS, this is not applicable. | Change the NIS domainname to a value difficult to guess. Consult vendor documentation for the required procedure. |
| V-12028 | CCI-000366 | medium | The system vulnerability assessment tool, host-based intrusion detection tool, and file integrity tool must notify the SA and the IAO of a security breach or a suspected security breach. | Timely notifications of potential security compromises minimize the potential damage. Minimally, the system must log these events and the SA and the IAO will receive the notifications during the daily system log review. If feasible, active alerting (such as e-mail or paging) should be employed consistent with the site’s established operations management systems and procedures. | For each security tool on the system, determine if the tool is configured to notify the IAO and SA of any detected security problem. If such notifications are not configured, this is a finding. | Configure the security tools on the system to notify the IAO and SA when any security issues are detected. |
| V-12030 | CCI-000366 | medium | The system's access control program must be configured to grant or deny system access to specific hosts. | If the system's access control program is not configured with appropriate rules for allowing and denying access to system network resources, services may be accessible to unauthorized hosts. | Check for the existence of the "/etc/hosts.allow" and "/etc/hosts.deny" files. Procedure: # ls -la /etc/hosts.allow # ls -la /etc/hosts.deny If either file does not exist, this is a finding. Check for the presence of a "default deny" entry. Procedure: # grep "ALL: ALL" /etc/hosts.deny If the "ALL: ALL" entry is not present the "/etc/hosts.deny" file, any TCP service from a host or network not matching other rules will be allowed access. If the entry is not in "/etc/hosts.deny", this is a finding. | Edit the "/etc/hosts.all" and "/etc/hosts.deny" files to configure access restrictions. |
| V-12038 | CCI-000225 | medium | The /etc/securetty file must be group-owned by root, sys, or bin. | The securetty file contains the list of terminals permitting direct root logins. It must be protected from unauthorized modification. | Check /etc/securetty group ownership: # ls -lL /etc/securetty If /etc/securetty is not group owned by root, sys, or bin, then this is a finding. | Change the group-owner of /etc/securetty to root, sys, or bin. Example: # chgrp root /etc/securetty |
| V-12039 | CCI-000225 | medium | The /etc/securetty file must be owned by root. | The securetty file contains the list of terminals permitting direct root logins. It must be protected from unauthorized modification. | Check /etc/securetty ownership. Procedure: # ls -lL /etc/securetty If /etc/securetty is not owned by root, this is a finding. | Change the owner of the /etc/securetty file to root. Procedure: # chown root /etc/securetty |
| V-12040 | CCI-000225 | medium | The /etc/securetty file must have mode 0640 or less permissive. | The securetty file contains the list of terminals permitting direct root logins. It must be protected from unauthorized modification. | Check /etc/securetty permissions. Procedure: # ls -lL /etc/securetty If /etc/securetty has a mode more permissive than 0600, this is a finding. | Change the mode of the /etc/securetty file to 0600. Procedure: # chmod 0600 /etc/securetty |
| V-12049 | CCI-000305 | medium | Network analysis tools must not be installed. | Network analysis tools allow for the capture of network traffic visible to the system. | Determine if any network analysis tools are installed. Procedure: # find / -name ethereal # find / -name wireshark # find / -name tshark # find / -name nc # find / -name tcpdump # find / -name snoop If any network analysis tools are found, this is a finding | Remove each network analysis tool binary from the system. Remove package items with a package manager, others remove the binary directly. Procedure: Find the binary file: # find / -name <Item to be removed> Find the package, if any, to which it belongs: # rpm -qf <binary file> Remove the package if it does not also include other software: # rpm -e <package name> or # yum remove <package name> If the item to be removed is not in a package, or the entire package cannot be removed because of other software it provides, remove the item's binary file. # rm <binary file> |
| V-12765 | CCI-001668 | medium | The system must use and update a DoD-approved virus scan program. | Virus scanning software can be used to protect a system from penetration from computer viruses and to limit their spread through intermediate systems. The virus scanning software should be configured to perform scans dynamically on accessed files. If this capability is not available, the system must be configured to scan, at a minimum, all altered files on the system on a daily basis. If the system processes inbound SMTP mail, the virus scanner must be configured to scan all received mail. | Check for the existence of a cron job to execute the McAfee command line scan tool (uvscan) daily. Other tools may be available but will have to be manually reviewed if they are installed. In addition, the definitions files should not be older than 7 days. Check if uvscan scheduled to run: # grep uvscan /var/spool/cron/* # grep uvscan /etc/cron.d/* # grep uvscan /etc/cron.daily/* # grep uvscan /etc/cron.hourly/* # grep uvscan /etc/cron.monthly/* # grep uvscan /etc/cron.weekly/* If a virus scanner is not being run daily and an exception has not been documented with the IAO, this is a finding. Perform the following command to ensure the virus definition signature files are not older than 7 days. The default uvscan install directory is /usr/local/uvscan. # cd <uvscan install directory> # ls -la avvscan.dat avvnames.dat avvclean.dat If the virus definitions are older than 7 days, this is a finding. | Install McAfee command line virus scan tool, or an appropriate alternative. Ensure the virus signature definition files are no older than 7 days. Configure the system to run a virus scan on altered files dynamically or daily. If daily scans impede operations, justify, document, and obtain IAO approval for alternate scheduling. |
| V-22290 | CCI-000366 | medium | The system clock must be synchronized continuously, or at least daily. | A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. Internal system clocks tend to drift and require periodic resynchronization to ensure their accuracy. Software, such as ntpd, can be used to continuously synchronize the system clock with authoritative sources. Alternatively, the system may be synchronized periodically, with a maximum of one day between synchronizations. If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable. | Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/* for the presence of an "ntpd -qg" job to run at least daily, which should have asterisks (*) in columns 3, 4, and 5. Check the daily cron directory (/etc/cron.daily) for any script running "ntpd -qg". Check for a running NTP daemon. # ps ax | grep ntpd If none of the above checks are successful, this is a finding. | Enable the NTP daemon for continuous synchronization. # service ntpd start ; chkconfig ntpd on OR Add a daily or more frequent cronjob to perform synchronization using ntpdate. |
| V-22291 | CCI-000160 | medium | The system must use at least two time sources for clock synchronization. | A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. For redundancy, two time sources are required so synchronization continues to function if one source fails. If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable. Note: For the network time protocol (NTP), the requirement is two servers, but it is recommended to configure at least four distinct time servers which allow NTP to effectively exclude a time source not consistent with the others. The system's local clock must be excluded from the count of time sources. | Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/*, or scripts in the /etc/cron.daily directory for the presence of an "ntpd -qg" job. If the "ntpd -qg" command is not invoked with at least two external NTP servers listed, this is a finding. Check the NTP daemon configuration for at least two external servers. # grep ^server /etc/ntp.conf | egrep -v '(127.127.1.0|127.127.1.1)' If less than two servers or external reference clocks (127.127.x.x other than 127.127.1.0 or 127.127.1.1) are listed, this is a finding. | If using "ntpd -qg", add additional NTP servers to the cron job running "ntpd -qg". If using the NTP daemon, add an additional "server" line to /etc/ntp.conf for each additional NTP server. |
| V-22292 | CCI-000160 | low | The system must use local time sources to the enclave. | A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. The network architecture should provide multiple time servers within an enclave providing local service to the enclave and synchronize with time sources outside of the enclave. If this server is an enclave time server, this requirement is not applicable. If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable. | Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/*, or scripts in the /etc/cron.daily directory for the presence of an "ntpd -qg" job. If the "ntpd -qg" command is invoked with NTP servers outside of the enclave, this is a finding. Check the NTP daemon configuration for NTP servers. # grep ^server /etc/ntp.conf | grep -v 127.127.1.1 If an NTP server is listed outside of the enclave, this is a finding. | If using "ntpd -qg", remove NTP servers external to the enclave from the cron job running "ntpd -qg". If using the NTP daemon, remove the "server" line from /etc/ntp.conf for each NTP server external to the enclave. |
| V-22294 | CCI-000225 | medium | The time synchronization configuration file (such as /etc/ntp.conf) must be owned by root. | A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not owned by a system account, unauthorized modifications could result in the failure of time synchronization. | Check the ownership of the NTP configuration file. # ls -l /etc/ntp.conf If the owner is not root, this is a finding. | Change the owner of the NTP configuration file. # chown root /etc/ntp.conf |
| V-22295 | CCI-000225 | medium | The time synchronization configuration file (such as /etc/ntp.conf) must be group-owned by root, bin, or sys. | A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not owned by a system group, unauthorized modifications could result in the failure of time synchronization. | Check the group ownership of the NTP configuration file. Procedure: # ls -lL /etc/ntp.conf If the group owner is not root, bin, or sys, this is a finding. | Change the group-owner of the NTP configuration file. Procedure: # chgrp root /etc/ntp.conf |
| V-22296 | CCI-000225 | medium | The time synchronization configuration file (such as /etc/ntp.conf) must have mode 0640 or less permissive. | A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not protected, unauthorized modifications could result in the failure of time synchronization. | Check the mode for the NTP configuration file is not more permissive than 0640. # ls -l /etc/ntp.conf If the mode is more permissive than 0640, this is a finding. | Change the mode of the NTP configuration file to 0640 or more restrictive. # chmod 0640 /etc/ntp.conf |
| V-22297 | CCI-000225 | medium | The time synchronization configuration file (such as /etc/ntp.conf) must not have an extended ACL. | A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. If an illicit time source is used for synchronization, the integrity of system logs and the security of the system could be compromised. If the configuration files controlling time synchronization are not protected, unauthorized modifications could result in the failure of time synchronization. | Check the NTP configuration file has no extended ACL. # ls -l /etc/ntp.conf If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the NTP configuration file. # setfacl --remove-all /etc/ntp.conf |
| V-22298 | CCI-000054 | low | The system must limit users to 10 simultaneous system logins, or a site-defined number, in accordance with operational requirements. | Limiting simultaneous user logins can insulate the system from denial of service problems caused by excessive logins. Automated login processes operating improperly or maliciously may result in an exceptional number of simultaneous login sessions. If the defined value of 10 logins does not meet operational requirements, the site may define the permitted number of simultaneous login sessions based on operational requirements. This limit is for the number of simultaneous login sessions for EACH user account. This is NOT a limit on the total number of simultaneous login sessions on the system. | Check for a default maxlogins line in the /etc/security/limits.conf and /etc/security/limits.d/* files. Procedure: #grep maxlogins /etc/security/limits.conf /etc/security/limits.d/* The default maxlimits should be set to a max of 10 or a documented site defined number: * - maxlogins 10 If no such line exists, this is a finding. | Add a "maxlogins" line such as "* hard maxlogins 10" to /etc/security/limits.conf or a file in /etc/security/limits.d. The enforced maximum should be defined by site requirements and policy. |
| V-22299 | CCI-000052 | low | The system must display the date and time of the last successful account login upon login. | Providing users with feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use. | Check that pam_lastlog is used and not silent, or that the SSH daemon is configured to display last login information. # grep pam_lastlog /etc/pam.d/sshd If pam_lastlog is present, and does not have the "silent" option, this is not a finding. # grep -i PrintLastLog /etc/ssh/sshd_config If PrintLastLog is not present in the configuration, this is not a finding. This is the default setting. If PrintLastLog is present in the configuration and set to "yes" (case insensitive), this is not a finding. Otherwise, this is a finding. | Implement pam_lastlog, or enable PrintLastLog in the SSH daemon. To enable pam_lastlog, add a line such as "session required pam_lastlog.so" to /etc/pam.d/sshd. To enable PrintLastLog in the SSH daemon, remove any lines disabling this option from /etc/ssh/sshd_config. |
| V-22301 | CCI-000061 | low | The system must display a publicly-viewable pattern during a graphical desktop environment session lock. | To protect the on-screen content of a session, it must be replaced with a publicly-viewable pattern upon session lock. Examples of publicly viewable patterns include screen saver patterns, photographic images, solid colors, or a blank screen, so long as none of those patterns convey sensitive information. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices, as well as, to graphical desktop environments provided to remote systems using remote access protocols. | Determine if a publicly-viewable pattern is displayed during a session lock. Some screensaver themes available but not included in the RHEL distribution use a snapshot of the current screen as a graphic. This theme does not qualify as a publicly-viewable pattern. If the session lock pattern is not publicly-viewable this is a finding. | Configure the system to display a publicly-viewable pattern during a session lock. This is done graphically by selecting a screensaver theme using gnome-screensaver-preferences command. Any of the themes distributed with RHEL may be used including "Blank Screen". |
| V-22302 | CCI-000205 | medium | The system must enforce compliance of the entire password during authentification. | Some common password hashing schemes only process the first eight characters of a user's password, which reduces the effective strength of the password. | Verify no password hash in /etc/passwd or /etc/shadow begins with a character other than an underscore (_) or dollar sign ($). # cut -d ':' -f2 /etc/passwd # cut -d ':' -f2 /etc/shadow If any password hash is present that does not have an initial underscore (_) or dollar sign ($) character, this is a finding. | Change the passwords for all accounts using non-compliant password hashes. (This requires GEN000590 is already met.) |
| V-22303 | CCI-000803 | medium | The system must use a FIPS 140-2 approved cryptographic hashing algorithm for generating account password hashes. | Systems must employ cryptographic hashes for passwords using the SHA-2 family of algorithms or FIPS 140-2 approved successors. The use of unapproved algorithms may result in weak password hashes more vulnerable to compromise. | Verify the algorithm used for password hashing is of the SHA-2 family. # egrep "password .* pam_unix.so" /etc/pam.d/system-auth-ac If the line indicates the hash algorithm is not set to sha256 or sha512, this is a finding. | Change the default password algorithm. # authconfig --passalgo=sha512 --update |
| V-22304 | CCI-000196 | medium | The password hashes stored on the system must have been generated using a FIPS 140-2 approved cryptographic hashing algorithm. | Systems must employ cryptographic hashes for passwords using the SHA-2 family of algorithms or FIPS 140-2 approved successors. The use of unapproved algorithms may result in weak password hashes more vulnerable to compromise. | Check all password hashes in /etc/passwd or /etc/shadow begin with '$5$' or '$6$'. Procedure: # cut -d ':' -f2 /etc/passwd # cut -d ':' -f2 /etc/shadow Any password hashes present not beginning with '$5$' or '$6$', is a finding. | Change the passwords for all accounts using non-compliant password hashes. (This requires GEN000590 is already met.) |
| V-22305 | CCI-000193 | medium | The system must require passwords contain at least one lowercase alphabetic character. | To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use. | Check /etc/pam.d/system-auth for lcredit setting. Procedure: Check the password lcredit option # grep pam_cracklib.so /etc/pam.d/system-auth Confirm the lcredit option is set to -1 as in the example: password required pam_cracklib.so lcredit=-1 There may be other options on the line. If no such line is found, or the lcredit is not -1 this is a finding. | Edit "/etc/pam.d/system-auth" to include the line: password required pam_cracklib.so lcredit=-1 prior to the "password include system-auth-ac" line. |
| V-22306 | CCI-000195 | medium | The system must require at least four characters be changed between the old and new passwords during a password change. | To ensure password changes are effective in their goals, the system must ensure that old and new passwords have significant differences. Without significant changes, new passwords may be easily guessed based on the value of a previously compromised password. | Check /etc/pam.d/system-auth for a pam_cracklib parameter difok. Procedure: # grep difok /etc/pam.d/system-auth If difok is not present, or has a value less than 4, this is a finding. Check for system-auth-ac inclusions. # grep -c system-auth-ac /etc/pam.d/* If the system-auth-ac file is included anywhere # more /etc/pam.d/system-auth-ac | grep difok If system-auth-ac is included anywhere and difok is not present, or has a value less than 4, this is a finding. Ensure the passwd command uses the system-auth settings. # grep system-auth /etc/pam.d/passwd If a line "password include system-auth" is not found then the password checks in system-auth will not be applied to new passwords. | If /etc/pam.d/system-auth references /etc/pam.d/system-auth-ac refer to the man page for system-auth-ac for a description of how to add options not configurable with authconfig. Edit /etc/pam.d/system-auth and add or edit a pam_cracklib entry with an difok parameter set equal to or greater than 4. |
| V-22307 | CCI-000189 | medium | The system must prevent the use of dictionary words for passwords. | An easily guessable password provides an open door to any external or internal malicious intruder. Many computer compromises occur as the result of account name and password guessing. This is generally done by someone with an automated script that uses repeated logon attempts until the correct account and password pair is guessed. Utilities, such as cracklib, can be used to validate passwords are not dictionary words and meet other criteria during password changes. | Check /etc/pam.d/system-auth for pam_cracklib configuration. Procedure: # grep pam_cracklib /etc/pam.d/system-auth* If pam_cracklib is not present. This is a finding. If pam_cracklib is present only in /etc/pam.d/system-auth-ac: ensure that /etc/pam.d/system-auth includes /etc/pam.d/system-auth-ac. #grep system-auth-ac /etc/pam.d/system-auth This should return: auth include system-auth-ac account include system-auth-ac password include system-auth-ac session include system-auth-ac /etc/pam.d/system-auth-ac should only be included by /etc/pam.d/system-auth. All other pam files should include /etc/pam.d/system-auth. If pam_cracklib is not defined in /etc/pam.d/system-auth either directly or through inclusion of system-auth-ac, this is a finding. Ensure the passwd command uses the system-auth settings. # grep system-auth /etc/pam.d/passwd If a line "password include system-auth" is not found then the password checks in system-auth will not be applied to new passwords, this is a finding. | If /etc/pam.d/system-auth references /etc/pam.d/system-auth-ac refer to the man page for system-auth-ac for a description of how to add options not configurable with authconfig. Edit /etc/pam.d/system-auth and configure pam_cracklib by adding a line such as "password required pam_cracklib.so" |
| V-22308 | CCI-000009 | low | The system must restrict the ability to switch to the root user to members of a defined group. | Configuring a supplemental group for users permitted to switch to the root user prevents unauthorized users from accessing the root account, even with knowledge of the root credentials. | Check /etc/pam.d/su uses pam_wheel. # grep pam_wheel /etc/pam.d/su If pam_wheel is not present, or is commented out, this is a finding. | Edit /etc/pam.d/su and uncomment or add a line such as "auth required pam_wheel.so". If necessary, create a "wheel" group and add administrative users to the group. |
| V-22309 | CCI-000225 | medium | The root account's home directory must not have an extended ACL. | File system extended ACLs provide access to files beyond what is allowed by the unix permissions of the files. | Check the root account's home directory has no extended ACL. # grep "^root" /etc/passwd | awk -F":" '{print $6}' # ls -ld <root home directory> If the permissions include a '+' the directory has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the root account's home directory. # setfacl --remove-all <root home directory> |
| V-22310 | CCI-000366 | medium | The root account's library search path must be the system default and must contain only absolute paths. | The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon or two consecutive colons, this is interpreted as the current working directory. Entries starting with a slash (/) are absolute paths. | Check the LD_LIBRARY_PATH environment variable is empty or not defined for the root user. # echo $LD_LIBRARY_PATH If a path list is returned, this is a finding. | Edit the root user initialization files and remove any definition of LD_LIBRARY_PATH. |
| V-22311 | CCI-000366 | medium | The root account's list of preloaded libraries must be empty. | The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries relative to the current working directory, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with (/) are absolute paths. | Check the LD_PRELOAD environment variable is empty or not defined for the root user. # echo $LD_PRELOAD If a path list is returned, this is a finding. | Edit the root user initialization files and remove any definition of LD_PRELOAD. |
| V-22312 | CCI-000366 | medium | All files and directories must have a valid group-owner. | Files without a valid group owner may be unintentionally inherited if a group is assigned the same GID as the GID of the files without a valid group-owner. | Search the system for files without a valid group-owner. # find / -nogroup If any files are found, this is a finding. | Change the group-owner for each file without a valid group-owner. # chgrp avalidgroup /tmp/a-file-without-a-valid-group-owner |
| V-22313 | CCI-000225 | medium | All network services daemon files must not have extended ACLs. | Restricting permission on daemons will protect them from unauthorized modification and possible system compromise. | Check network services daemon files have no extended ACLs. # ls -la /usr/sbin If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. Note: Network daemons not residing in these directories must also be checked. | Remove the extended ACL from the file. # setfacl --remove-all /usr/sbin/* |
| V-22314 | CCI-001499 | medium | All system command files must not have extended ACLs. | Restricting permissions will protect system command files from unauthorized modification. System command files include files present in directories used by the operating system for storing default system executables and files present in directories included in the system's default executable search paths. | Check all system command files have no extended ACLs. # ls -lL /etc /bin /usr/bin /usr/lbin /usr/usb /sbin /usr/sbin If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all [file with extended ACL] |
| V-22315 | CCI-001314 | medium | System log files must not have extended ACLs, except as needed to support authorized software. | If the system log files are not protected, unauthorized users could change the logged data, eliminating its forensic value. Authorized software may be given log file access through the use of extended ACLs when needed and configured to provide the least privileges required. | Verify system log files have no extended ACLs. Procedure: # ls -lL /var/log If the permissions include a '+', the file has an extended ACL. If an extended ACL exists, verify with the SA if the ACL is required to support authorized software and provides the minimum necessary permissions. If an extended ACL exists providing access beyond the needs of authorized software, this is a finding. | Remove the extended ACL from the file. Procedure: # setfacl --remove-all [file with extended ACL] |
| V-22316 | CCI-000225 | low | All manual page files must not have extended ACLs. | If manual pages are compromised, misleading information could be inserted, causing actions to compromise the system. | Verify all manual page files have no extended ACLs. # ls -lL /usr/share/man /usr/share/info /usr/share/infopage If the permissions include a '+', the file has an extended ACL this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /usr/share/man/* /usr/share/info/* /usr/share/infopage/* |
| V-22317 | CCI-001499 | medium | All library files must not have extended ACLs. | Unauthorized access could destroy the integrity of the library files. | Verify system libraries have no extended ACLs. # ls -lL /usr/lib/* /lib/* | grep "+ " If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and has not been approved by the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /usr/lib/* /lib/* |
| V-22318 | CCI-000225 | medium | NIS/NIS+/yp command files must not have extended ACLs. | NIS/NIS+/yp files are part of the system's identification and authentication processes and are critical to system security. ACLs on these files could result in unauthorized modification, which could compromise these processes and the system. | Verify NIS/NIS+/yp files have no extended ACLs. # ls -lL /var/yp/* If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /var/yp/* |
| V-22319 | CCI-000225 | medium | The /etc/resolv.conf file must be owned by root. | The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging. | Verify the /etc/resolv.conf file is owned by root. # ls -l /etc/resolv.conf If the file is not owned by root, this is a finding. | Change the owner of the /etc/resolv.conf file to root. # chown root /etc/resolv.conf |
| V-22320 | CCI-000225 | medium | The /etc/resolv.conf file must be group-owned by root, bin, or sys. | The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging. | Check the group ownership of the resolv.conf file. Procedure: # ls -lL /etc/resolv.conf If the file is not group-owned by root, bin, or sys, this is a finding. | Change the group-owner of the /etc/resolv.conf file to root, bin, or sys. Procedure: # chgrp root /etc/resolv.conf |
| V-22321 | CCI-000225 | medium | The /etc/resolv.conf file must have mode 0644 or less permissive. | The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging. | Check the mode of the /etc/resolv.conf file. # ls -l /etc/resolv.conf If the file mode is not 0644, this is a finding. | Change the mode of the /etc/resolv.conf file to 0644. # chmod 0644 /etc/resolv.conf |
| V-22322 | CCI-000225 | medium | The /etc/resolv.conf file must not have an extended ACL. | The resolv.conf (or equivalent) file configures the system's DNS resolver. DNS is used to resolve host names to IP addresses. If DNS configuration is modified maliciously, host name resolution may fail or return incorrect information. DNS may be used by a variety of system security functions such as time synchronization, centralized authentication, and remote system logging. | Verify /etc/resolv.conf has no extended ACL. # ls -l /etc/resolv.conf If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/resolv.conf |
| V-22323 | CCI-000225 | medium | The /etc/hosts file must be owned by root. | The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging. | Verify the /etc/hosts file is owned by root. # ls -l /etc/hosts If the file is not owned by root, this is a finding. | Change the owner of the /etc/hosts file to root. # chown root /etc/hosts |
| V-22324 | CCI-000225 | medium | The /etc/hosts file must be group-owned by root, bin, or sys. | The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging. | Check the /etc/hosts file's group ownership. Procedure: # ls -lL /etc/hosts If the file is not group-owned by root, bin, or sys, this is a finding. | Change the group-owner of the /etc/hosts file to root, sys, or bin. Procedure: # chgrp root /etc/hosts |
| V-22325 | CCI-000225 | medium | The /etc/hosts file must have mode 0644 or less permissive. | The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging. | Check the mode of the /etc/hosts file. # ls -l /etc/hosts If the file mode is not 0644, this is a finding. | Change the mode of the /etc/hosts file to 0644. # chmod 0644 /etc/hosts |
| V-22326 | CCI-000225 | medium | The /etc/hosts file must not have an extended ACL. | The /etc/hosts file (or equivalent) configures local host name to IP address mappings that typically take precedence over DNS resolution. If this file is maliciously modified, it could cause the failure or compromise of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging. | Verify /etc/hosts has no extended ACL. # ls -l /etc/hosts If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/hosts |
| V-22327 | CCI-000225 | medium | The /etc/nsswitch.conf file must be owned by root. | The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security. | Verify the /etc/nsswitch.conf file is owned by root. # ls -l /etc/nsswitch.conf If the file is not owned by root, this is a finding. | Change the owner of the /etc/nsswitch.conf file to root. # chown root /etc/nsswitch.conf |
| V-22328 | CCI-000225 | medium | The /etc/nsswitch.conf file must be group-owned by root, bin, or sys. | The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security. | Check the group ownership of the nsswitch.conf file. Procedure: # ls -lL /etc/nsswitch.conf If the file is not group-owned by root, bin or sys, this is a finding. | Change the group-owner of the /etc/nsswitch.conf file to root, bin or sys. Procedure: # chgrp root /etc/nsswitch.conf |
| V-22329 | CCI-000225 | medium | The /etc/nsswitch.conf file must have mode 0644 or less permissive. | The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security. | Check the mode of the /etc/nsswitch.conf file. # ls -l /etc/nsswitch.conf If the file mode is not 0644, this is a finding. | Change the mode of the /etc/nsswitch.conf file to 0644 or less permissive. # chmod 0644 /etc/nsswitch.conf |
| V-22330 | CCI-000225 | medium | The /etc/nsswitch.conf file must not have an extended ACL. | The nsswitch.conf file (or equivalent) configures the source of a variety of system security information including account, group, and host lookups. Malicious changes could prevent the system from functioning or compromise system security. | Verify /etc/nsswitch.conf has no extended ACL. # ls -l /etc/nsswitch.conf If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/nsswitch.conf |
| V-22332 | CCI-000225 | medium | The /etc/passwd file must be owned by root. | The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. | Verify the /etc/passwd file is owned by root. # ls -l /etc/passwd If the file is not owned by root, this is a finding. | Change the owner of the /etc/passwd file to root. # chown root /etc/passwd |
| V-22333 | CCI-000225 | medium | The /etc/passwd file must be group-owned by root, bin, or sys. | The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. | Check the group ownership of the passwd file. Procedure: # ls -lL /etc/passwd If the file is not group-owned by root, bin or sys, this is a finding. | Change the group-owner of the /etc/passwd file to root, bin or sys. Procedure: # chgrp root /etc/passwd |
| V-22334 | CCI-000225 | medium | The /etc/passwd file must not have an extended ACL. | File system ACLs can provide access to files beyond what is allowed by the mode numbers of the files. The /etc/passwd file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. | Verify /etc/passwd has no extended ACL. # ls -l /etc/passwd If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/passwd |
| V-22335 | CCI-000225 | medium | The /etc/group file must be owned by root. | The /etc/group file is critical to system security and must be owned by a privileged user. The group file contains a list of system groups and associated information. | Verify the /etc/group file is owned by root. # ls -l /etc/group If the file is not owned by root, this is a finding. | Change the owner of the /etc/group file to root. # chown root /etc/group |
| V-22336 | CCI-000225 | medium | The /etc/group file must be group-owned by root, bin, or sys. | The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information. | Check the group ownership of the /etc/group file. Procedure: # ls -lL /etc/group If the file is not group-owned by root, bin or sys, this is a finding. | Change the group-owner of the /etc/group file. Procedure: # chgrp root /etc/group |
| V-22337 | CCI-000225 | medium | The /etc/group file must have mode 0644 or less permissive. | The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information. | Check the mode of the /etc/group file. # ls -l /etc/group If the file mode is more permissive than 0644, this is a finding. | Change the mode of the /etc/group file to 0644 or less permissive. # chmod 0644 /etc/group |
| V-22338 | CCI-000225 | medium | The /etc/group file must not have an extended ACL. | The /etc/group file is critical to system security and must be protected from unauthorized modification. The group file contains a list of system groups and associated information. | Verify /etc/group has no extended ACL. # ls -l /etc/group If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/group |
| V-22339 | CCI-000225 | medium | The /etc/shadow file (or equivalent) must be group-owned by root, bin,or sys. | The /etc/shadow file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root. | Check the ownership of the /etc/shadow file. Procedure: # ls -lL /etc/shadow If the file is not group-owned by root, bin, or sys, this is a finding. | Change the group-owner of the /etc/shadow file. Procedure: # chgrp root /etc/shadow |
| V-22340 | CCI-000225 | medium | The /etc/shadow file must not have an extended ACL. | The /etc/shadow file contains the list of local system accounts. It is vital to system security and must be protected from unauthorized modification. The file also contains password hashes which must not be accessible to users other than root. | Verify /etc/shadow has no extended ACL. # ls -l /etc/shadow If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/shadow |
| V-22341 | CCE-4210-1 | medium | The /etc/gshadow file must be owned by root. | The /etc/gshadow file is critical to system security and must be owned by a privileged user. The /etc/gshadow file contains a list of system groups and hashes for group passwords. | Check the /etc/gshadow file is owned by root. # ls -l /etc/gshadow If the file is not owned by root, this is a finding. | Change the owner of the /etc/gshadow file to root. # chown root /etc/gshadow |
| V-22342 | CCI-000225 | medium | The /etc/gshadow file must be group-owned by root. | The /etc/gshadow file is critical to system security and must be protected from unauthorized modification. The /etc/gshadow file contains a list of system groups and hashes for group passwords. | Check the /etc/gshadow file is group-owned by root. # ls -l /etc/gshadow If the file is not group-owned by root, this is a finding. | Change the group-owner of the /etc/gshadow file to root. # chgrp root /etc/gshadow |
| V-22343 | CCI-000225 | medium | The /etc/gshadow file must have mode 0400. | The /etc/gshadow file is critical to system security and must be protected from unauthorized modification. The /etc/gshadow file contains a list of system groups and hashes for group passwords. | Check the mode of the /etc/gshadow file. # ls -l /etc/gshadow If the file mode is more permissive than 0400, this is a finding. | Change the mode of the /etc/gshadow file to 0400 or less permissive. # chmod 0400 /etc/gshadow |
| V-22344 | CCI-000225 | medium | The /etc/gshadow file must not have an extended ACL. | The /etc/gshadow file is critical to system security and must be protected from unauthorized modification. The /etc/gshadow file contains a list of system groups and hashes for group passwords. | Check /etc/gshadow has no extended ACL. # ls -l /etc/gshadow If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/gshadow |
| V-22347 | CCI-000201 | medium | The /etc/passwd file must not contain password hashes. | If password hashes are readable by non-administrators, the passwords are subject to attack through lookup tables or cryptographic weaknesses in the hashes. | Verify no password hashes are present in /etc/passwd. # cut -d : -f 2 /etc/passwd | grep -v '^(x|\*)$' If any password hashes are returned, this is a finding. | Migrate /etc/passwd password hashes to /etc/shadow. # pwconv |
| V-22348 | CCI-000225 | medium | The /etc/group file must not contain any group password hashes. | Group passwords are typically shared and should not be used. Additionally, if password hashes are readable by non-administrators, the passwords are subject to attack through lookup tables or cryptographic weaknesses in the hashes. | Check the /etc/group file for password hashes. # cut -d : -f 2 /etc/group | egrep -v '^(x|!)$' If any password hashes are returned, this is a finding. | Edit /etc/group and change the password field to an exclamation point (!) to lock the group password. |
| V-22349 | CCI-000366 | medium | The /etc/gshadow file must not contain any group password hashes. | Group passwords are typically shared and should not be used. | Check the /etc/gshadow file for password hashes. # cut -d : -f 2 /etc/gshadow | egrep -v '^(x|!!)$' If any password hashes are returned, this is a finding. | Edit /etc/gshadow and change the password field to an exclamation point (!) to lock the group password. |
| V-22350 | CCI-000225 | low | User home directories must not have extended ACLs. | Excessive permissions on home directories allow unauthorized access to user files. | Verify user home directories have no extended ACLs. # cut -d : -f 6 /etc/passwd | xargs -n1 ls -ld If the permissions include a '+', the file has an extended ACL this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all [user home directory with extended ACL] |
| V-22351 | CCI-000225 | medium | All files and directories contained in user home directories must be group-owned by a group of which the home directory's owner is a member. | If a user's files are group-owned by a group of which the user is not a member, unintended users may be able to access them. | Check the contents of user home directories for files group-owned by a group of which the home directory's owner is not a member. 1. List the user accounts. # cut -d : -f 1 /etc/passwd 2. For each user account, get a list of GIDs for files in the user's home directory. # find ~username -printf %G\\n | sort | uniq 3. Obtain the list of GIDs where the user is a member. # id -G username 4. Check the GID lists. If there are GIDs in the file list not present in the user list, this is a finding. | Change the group of a file not group-owned by a group of which the home directory's owner is a member. # chgrp <group with user as member> <file with bad group ownership> Document all changes. |
| V-22352 | CCI-000225 | medium | All files and directories contained in user home directories must not have extended ACLs. | Excessive permissions allow unauthorized access to user files. | Check the contents of user home directories for files with extended ACLs. # cut -d : -f 6 /etc/passwd | xargs -n1 -IDIR ls -alLR DIR If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all <user file with extended ACL> |
| V-22353 | CCI-000225 | medium | All run control scripts must have no extended ACLs. | If the startup files are writable by other users, they could modify the startup files to insert malicious commands into the startup files. | Verify run control scripts have no extended ACLs. # ls -lL /etc/rc* /etc/init.d If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all <run control script with extended ACL> |
| V-22354 | CCI-000366 | medium | Run control scripts' library search paths must contain only absolute paths. | The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths. | Verify run control scripts' library search paths. # grep -r LD_LIBRARY_PATH /etc/rc* /etc/init.d This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/) this is a relative path, this is a finding. | Edit the run control script and remove the relative path entry from the library search path variable. |
| V-22355 | CCI-000366 | medium | Run control scripts' lists of preloaded libraries must contain only absolute paths. | The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries relative to the current working directory, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths. | Verify run control scripts' library preload list. # grep -r LD_PRELOAD /etc/rc* /etc/init.d This variable is formatted as a colon-separated list of paths. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/) this is a relative path, this is a finding. | Edit the run control script and remove the relative path entry from the library preload variable. |
| V-22356 | CCI-000225 | medium | All global initialization files must not have extended ACLs. | Global initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. | Check global initialization files for extended ACLs: # ls -l /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|grep "\+ " If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # ls -l etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* 2>null|grep "\+ "|sed "s/^.* \///g"|xargs setfacl --remove-all |
| V-22357 | CCI-000225 | medium | Skeleton files must not have extended ACLs. | If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files. | Check skeleton files for extended ACLs: # ls -alL /etc/skel If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all [skeleton file with extended ACL] or: # ls -lL /etc/skel|grep "\+ "|sed "s/^.* \//|xargs setfacl --remove-all will remove all ACLs from the files. |
| V-22358 | CCI-000225 | medium | All skeleton files (typically in /etc/skel) must be group-owned by root, bin, sys, system, or other. | If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files. | Verify the skeleton files are group-owned by root. Procedure: # ls -alL /etc/skel If a skeleton file is not group-owned by root, bin, sys, system, or other this is a finding. | Change the group-owner of the skeleton file to root, bin, sys, system, or other. Procedure: # chgrp <group> /etc/skel/[skeleton file] or: # ls -L /etc/skel|xargs stat -L -c %G:%n|egrep -v "^(root|bin|sy|sytem|other):"|cut -d: -f2|chgrp root will change the group of all files not already one of the approved group to root. |
| V-22359 | CCI-000366 | medium | Global initialization files' library search paths must contain only absolute paths. | The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths. | Check the global initialization files' library search paths. Procedure: # grep LD_LIBRARY_PATH /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/) this is a relative path, this is a finding. | Edit the global initialization file and remove the relative path entry from the library search path variable. |
| V-22360 | CCI-000366 | medium | Global initialization files' lists of preloaded libraries must contain only absolute paths. | The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries relative to the current working directory, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths. | Check the global initialization files' library preload list. # grep -r LD_PRELOAD /etc/bashrc /etc/csh.cshrc /etc/csh.login /etc/csh.logout /etc/environment /etc/ksh.kshrc /etc/profile /etc/suid_profile /etc/profile.d/* This variable is formatted as a colon-separated list of paths. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/) this is a relative path, this is a finding. | Edit the global initialization file and remove the relative path entry from the library preload variable. |
| V-22361 | CCI-000225 | medium | Local initialization files must be group-owned by the user's primary group or root. | Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. | Check user home directories for local initialization files group-owned by a group other than the user's primary group or root. Procedure: # FILES=" .login .cshrc .logout .profile .bash_profile .bashrc .bash_logout .env .dtprofile .dispatch .emacs .exrc"; # for PWLINE in `cut -d: -f4,6 /etc/passwd`; do HOMEDIR=$(echo ${PWLINE}|cut -d: -f2);GROUP=$(echo ${PWLINE} | cut -d: -f1);for INIFILE in $FILES;do stat -c %g/%G:%n ${HOMEDIR}/${INIFILE} 2>null|egrep -v "${GROUP}";done;done If any file is not group-owned by root or the user's primary GID, this is a finding. | Change the group-owner of the local initialization file to the user's primary group, or root. # chgrp <user's primary GID> <user's local initialization file> Procedure: # FILES=".bashrc .bash_login .bash_logout .bash_profile .cshrc .kshrc .login .logout .profile .tcshrc .env .dtprofile .dispatch .emacs .exrc"; # for PWLINE in `cut -d: -f4,6 /etc/passwd`; do HOMEDIR=$(echo ${PWLINE}|cut -d: -f2);GROUP=$(echo ${PWLINE} | cut -d: -f1);for INIFILE in $FILES;do MATCH=$(stat -c %g/%G:%n ${HOMEDIR}/${INIFILE} 2>null|egrep -c -v "${GROUP}");if [ $MATCH != 0 ] ; then chgrp ${GROUP} ${HOMEDIR}/${INIFILE};fi;done;done |
| V-22362 | CCI-000225 | medium | Local initialization files must not have extended ACLs. | Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon logon. | Check user home directories for local initialization files with extended ACLs. # cut -d : -f 6 /etc/passwd | xargs -n1 -IDIR ls -alL DIR/.bashrc DIR/.bash_login DIR/.bash_logout DIR/.bash_profile DIR/.cshrc DIR/.kshrc DIR/.login DIR/.logout DIR/.profile DIR/.env DIR/.dtprofile DIR/.dispatch DIR/.emacs DIR/.exrc If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all <local initialization file with extended ACL> |
| V-22363 | CCI-000366 | medium | Local initialization files' library search paths must contain only absolute paths. | The library search path environment variable(s) contain a list of directories for the dynamic linker to search to find libraries. If this path includes the current working directory or other relative paths, libraries in these directories may be loaded instead of system libraries. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is interpreted as the current working directory. Paths starting with a slash (/) are absolute paths. | Verify local initialization files have library search path containing only absolute paths. Procedure: # cut -d: -f6 /etc/passwd |xargs -n1 -IDIR find DIR -name ".*" -type f -maxdepth 1 -exec grep -H LD_LIBRARY_PATH {} \; This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/) this is a relative path, this is a finding. | Edit the local initialization file and remove the relative path entry from the library search path variable. |
| V-22364 | CCI-000366 | medium | Local initialization files' lists of preloaded libraries must contain only absolute paths. | The library preload list environment variable contains a list of libraries for the dynamic linker to load before loading the libraries required by the binary. If this list contains paths to libraries relative to the current working directory, unintended libraries may be preloaded. This variable is formatted as a space-separated list of libraries. Paths starting with a slash (/) are absolute paths. | Verify local initialization files have library preload list containing only absolute paths. Procedure: # cut -d: -f6 /etc/passwd |xargs -n1 -IDIR find DIR -name ".*" -type f -maxdepth 1 -exec grep -H LD_PRELOAD {} \; This variable is formatted as a colon-separated list of paths. If there is an empty entry, such as a leading or trailing colon, or two consecutive colons, this is a finding. If an entry begins with a character other than a slash (/) this is a relative path, this is a finding. | Edit the local initialization file and remove the relative path entry from the library preload variable. |
| V-22365 | CCI-000225 | medium | All shell files must be group-owned by root, bin, sys, or system. | If shell files are group-owned by users other than root or a system group, they could be modified by intruders or malicious users to perform unauthorized actions. | If /etc/shells exists, check the group ownership of each shell referenced. Procedure: # cat /etc/shells | xargs -n1 ls -l Otherwise, check any shells found on the system. Procedure: # find / -name "*sh" | xargs -n1 ls -l If a shell is not group-owned by root, bin, sys, or system, this is a finding. | Change the group-owner of the shell to root, bin, sys, or system. Procedure: # chgrp root <shell> |
| V-22366 | CCI-000225 | medium | All shell files must not have extended ACLs. | Shells with world/group write permissions give the ability to maliciously modify the shell to obtain unauthorized access. | If /etc/shells exists, check the permissions of each shell referenced. # cat /etc/shells | xargs -n1 ls -lL Otherwise, check any shells found on the system. # find / -name "*sh" | xargs -n1 ls -lL If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all [shell] |
| V-22367 | CCI-000225 | medium | Audio devices must not have extended ACLs. | File system ACLs can provide access to files beyond what is allowed by the mode numbers of the files. | Check the permissions of audio devices. # ls -lL /dev/audio* /dev/snd/* If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all [device file] |
| V-22368 | CCI-000366 | medium | Removable media, remote file systems, and any file system not containing approved device files must be mounted with the "nodev" option. | The "nodev" (or equivalent) mount option causes the system to not handle device files as system devices. This option must be used for mounting any file system not containing approved device files. Device files can provide direct access to system hardware and can compromise security if not protected. | Check /etc/mtab and verify the "nodev" mount option is used on any filesystems mounted from removable media or network shares. If any filesystem mounted from removable media or network shares does not have this option, this is a finding. | Edit /etc/fstab and add the "nodev" option to any filesystems mounted from removable media or network shares. |
| V-22369 | CCI-000163 | medium | All system audit files must not have extended ACLs. | If a user can write to the audit logs, then audit trails can be modified or destroyed and system intrusion may not be detected. | Check the system audit log files for extended ACLs. Procedure: # grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs ls -l If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the system audit file(s). |
| V-22370 | CCI-001493 | low | System audit tool executables must be owned by root. | To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected. | Verify the audit tool executables are owned by root. # ls -l /sbin/auditctl /sbin/auditd /sbin/ausearch /sbin/aureport /sbin/autrace /sbin/audispd If any listed file is not owned by root, this is a finding. | Change the owner of the audit tool executable to root. # chown root [audit tool executable] |
| V-22371 | CCI-001493 | low | System audit tool executables must be group-owned by root, bin, sys, or system. | To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected. | Verify the audit tool executables are group-owned by root, bin, sys, or system. Procedure: # ls -lL /sbin/auditctl /sbin/auditd /sbin/ausearch /sbin/aureport /sbin/autrace /sbin/audispd If any listed file is not group-owned by root, bin, sys, or system, this is a finding. | Change the group-owner of the audit tool executable to root, bin, sys, or system. Procedure: # chgrp root <audit tool executable> |
| V-22372 | CCI-001493 | low | System audit tool executables must have mode 0750 or less permissive. | To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected. | Check the mode of audit tool executables. # ls -l /sbin/auditctl /sbin/auditd /sbin/ausearch /sbin/aureport /sbin/autrace /sbin/audispd If any listed file has a mode more permissive than 0750, this is a finding. | Change the mode of the audit tool executable to 0750, or less permissive. # chmod 0750 [audit tool executable] |
| V-22373 | CCI-001493 | low | System audit tool executables must not have extended ACLs. | To prevent unauthorized access or manipulation of system audit logs, the tools for manipulating those logs must be protected. | Check the permissions of audit tool executables. # ls -l /sbin/auditctl /sbin/auditd /sbin/ausearch /sbin/aureport /sbin/autrace /sbin/audispd If the permissions include a '+' the file has an extended ACL, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all [audit file] |
| V-22374 | CCI-000139 | low | The audit system must alert the SA in the event of an audit processing failure. | An accurate and current audit trail is essential for maintaining a record of system activity. If the system fails, the SA must be notified and must take prompt action to correct the problem. Minimally, the system must log this event and the SA will receive this notification during the daily system log review. If feasible, active alerting (such as e-mail or paging) should be employed consistent with the site’s established operations management systems and procedures. | Verify the /etc/audit/auditd.conf has the disk_full_action and disk_error_action parameters set. Procedure: # grep disk_full_action /etc/audit/audit.conf If the disk_full_action parameter is missing or set to "suspend" or "ignore" this is a finding. # grep disk_error_action /etc/audit/audit.conf If the disk_error_action parameter is missing or set to "suspend" or "ignore" this is a finding. | Edit /etc/audit/auditd.conf and set the disk_full_action and/or disk_error_action parameters to a valid setting of "syslog", "exec", "single" or "halt", adding the parameters if necessary. |
| V-22375 | CCI-000143 | medium | The audit system must alert the SA when the audit storage volume approaches its capacity. | An accurate and current audit trail is essential for maintaining a record of system activity. If the system fails, the SA must be notified and must take prompt action to correct the problem. Minimally, the system must log this event and the SA will receive this notification during the daily system log review. If feasible, active alerting (such as e-mail or paging) should be employed consistent with the site’s established operations management systems and procedures. | Check /etc/audit/auditd.conf for the space_left_action and action_mail_accnt parameters. If the space_left_action or the action_mail_accnt parameters are set to blanks, this is a finding. If the space_left_action is set to "syslog"the system logs the event, this is not a finding. If the space_left_action is set to "exec"the system executes a designated script. If this script informs the SA of the event, this is not a finding. If the space_left_action parameter is missing, this is a finding. If the space_left_action parameter is set to "ignore" or "suspend" no logging would be performed after the event, this is a finding. If the space_left_action parameter is set to "single" or "halt" this effectively stops the system causing a Denial of Service, this is a finding. If the space_left_action is set to "email" and the action_mail_acct parameter is not set to the e-mail address of the system administrator, this is a finding. The action_mail_acct parameter, if missing, defaults to "root". Note that if the email address of the system administrator is on a remote system "sendmail" must be available. | Edit /etc/audit/auditd.conf and set the space_left_action parameter to a valid setting other than "ignore". If the space_left_action parameter is set to "email" set the action_mail_acct parameter to an e-mail address for the system administrator. |
| V-22376 | CCI-000018 | low | The audit system must be configured to audit account creation. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises, and damages incurred during a system compromise. | Determine if execution of the useradd and groupadd executable are audited. # auditctl -l | egrep '(useradd|groupadd)' If either useradd or groupadd are not listed with a permissions filter of at least 'x', this is a finding. Determine if /etc/passwd, /etc/shadow, /etc/group, and /etc/gshadow are audited for appending. # auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow)' If any of these are not listed with a permissions filter of at least 'a', this is a finding. | Configure execute auditing of the useradd and groupadd executables. Add the following to audit.rules: -w /usr/sbin/useradd -p x -k useradd -w /usr/sbin/groupadd -p x -k groupadd Configure append auditing of the passwd, shadow, group, and gshadow files. Add the following to audit.rules: -w /etc/passwd -p a -k passwd -w /etc/shadow -p a -k shadow -w /etc/group -p a -k group -w /etc/gshadow -p a -k gshadow Restart the auditd service. |
| V-22377 | CCI-001403 | low | The audit system must be configured to audit account modification. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Determine if execution of the usermod and groupmod executable are audited. # auditctl -l | egrep '(usermod|groupmod)' If either useradd or groupadd are not listed with a permissions filter of at least 'w', this is a finding. Determine if /etc/passwd, /etc/shadow, /etc/group, and /etc/gshadow are audited for writing. # auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow)' If any of these are not listed with a permissions filter of at least 'w', this is a finding. | Configure execute auditing of the usermod and groupmod executables. Add the following to the audit.rules file: -w /usr/sbin/usermod -p x -k usermod -w /usr/sbin/groupmod -p x -k groupmod Configure append auditing of the passwd, shadow, group, and gshadow files. Add the following to the audit.rules file: -w /etc/passwd -p w -k passwd -w /etc/shadow -p w -k shadow -w /etc/group -p w -k group -w /etc/gshadow -p w -k gshadow Restart the auditd service. |
| V-22378 | CCI-001404 | low | The audit system must be configured to audit account disabling. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Determine if execution of the passwd executable is audited. # auditctl -l | grep /usr/bin/passwd If passwd is not listed with a permissions filter of at least 'x', this is a finding. | Configure execute auditing of the passwd executable. Add the following to the audit.rules file: -w /usr/bin/passwd -p x -k passwd Restart the auditd service. |
| V-22382 | CCI-001405 | low | The audit system must be configured to audit account termination. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Determine if execution of the userdel and groupdel executable are audited. # auditctl -l | egrep '(userdel|groupdel)' If either userdel or groupdel are not listed with a permissions filter of at least 'x', this is a finding. | Configure execute auditing of the userdel and groupdel executables. Add the following to the audit.rules file: -w /usr/sbin/userdel -p x -w /usr/sbin/groupdel -p x Restart the auditd service. |
| V-22383 | CCI-000126 | medium | The audit system must be configured to audit the loading and unloading of dynamic kernel modules. | Actions concerning dynamic kernel modules must be recorded as they are substantial events. Dynamic kernel modules can increase the attack surface of a system. A malicious kernel module can be used to substantially alter the functioning of a system, often with the purpose of hiding a compromise from the SA. | Determine if the init_module syscall is audited. # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "init_module" If the result does not contain "-S init_module", this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Configure auditing of the init_module syscalls. Add the following to the "etc/audit/audit.rules" or "etc/audit.rules" file: -a exit,always -S init_module Restart the auditd service. # service auditd restart |
| V-22384 | CCI-000225 | medium | The cron.allow file must not have an extended ACL. | A readable and/or writeable cron.allow file by other users than root could allow potential intruders and malicious users to use the file contents to help discern information, such as who is allowed to execute cron programs, which could be harmful to overall system and network security. | Check the permissions of the cron.allow file. # ls -l /etc/cron.allow If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/cron.allow |
| V-22385 | CCI-000225 | medium | Crontab files must be group-owned by root, cron, or the crontab creator's primary group. | To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured. | Check the group ownership of the crontab files. Procedure: # ls -lL /var/spool/cron # ls -lL /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls -lL /etc/cron*|grep -v deny If the group owner is not root or the crontab owner's primary group, this is a finding. | Change the group owner of the crontab file to root, cron, or the crontab's primary group. Procedure: # chgrp root [crontab file] |
| V-22386 | CCI-000225 | medium | Crontab files must not have extended ACLs. | To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. ACLs on crontab files may provide unauthorized access to the files. | Check the permissions of the crontab files. Procedure: # ls -lL /var/spool/cron # ls -lL /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls -lL /etc/cron*|grep -v deny If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all [crontab file] |
| V-22387 | CCI-000225 | medium | Cron and crontab directories must not have extended ACLs. | To protect the integrity of scheduled system jobs and to prevent malicious modification to these jobs, crontab files must be secured. ACLs on cron and crontab directories may provide unauthorized access to these directories. Unauthorized modifications to these directories or their contents may result in the addition of unauthorized cron jobs or deny service to authorized cron jobs. | Check the permissions of the crontab directories. Procedure: # ls -ld /var/spool/cron # ls -ld /etc/cron.d /etc/crontab /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly or # ls -ld /etc/cron*|grep -v deny If the permissions include a '+' the directory has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the directory. # setfacl --remove-all <crontab directory> |
| V-22388 | CCI-000225 | medium | The cron log files must not have extended ACLs. | Cron logs contain reports of scheduled system activities and must be protected from unauthorized access or manipulation. | Check the permissions of the file. Procedure: Check the configured cron log file found in the cron entry in /etc/syslog (normally /var/log/cron). # grep cron /etc/syslog.conf # ls -lL /var/log/cron If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /var/log/cron |
| V-22389 | CCI-000225 | medium | The cron.deny file must not have an extended ACL. | If there are excessive file permissions for the cron.deny file, sensitive information could be viewed or edited by unauthorized users. | Check the permissions of the file. # ls -lL /etc/cron.deny If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/cron.deny |
| V-22390 | CCI-000225 | medium | The at.allow file must not have an extended ACL. | File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Unauthorized modification of the at.allow file could result in Denial of Service to authorized "at" users and the granting of the ability to run "at" jobs to unauthorized users. | Check the permissions of the file. # ls -lL /etc/at.allow If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/at.allow |
| V-22391 | CCI-000225 | medium | The cron.allow file must be group-owned by root, bin, sys, or cron. | If the group of the cron.allow is not set to root, bin, sys, or cron, the possibility exists for an unauthorized user to view or edit the list of users permitted to use cron. Unauthorized modification of this file could cause Denial of Service to authorized cron users or provide unauthorized users with the ability to run cron jobs. | Check the group ownership of the file. Procedure: # ls -lL /etc/cron.allow If the file exists and is not group-owned by root, bin, sys or cron, this is a finding. | Change the group ownership of the file. Procedure: # chgrp root /etc/cron.allow |
| V-22392 | CCI-000225 | medium | The at.deny file must have mode 0600 or less permissive. | The "at" daemon control files restrict access to scheduled job manipulation and must be protected. Unauthorized modification of the at.deny file could result in Denial of Service to authorized "at" users or provide unauthorized users with the ability to run "at" jobs. | Check the permissions of the file. # ls -lL /etc/at.deny If the file has a mode more permissive than 0600, this is a finding. | Change the mode of the file. # chmod 0600 /etc/at.deny |
| V-22393 | CCI-000225 | medium | The at.deny file must not have an extended ACL. | The "at" daemon control files restrict access to scheduled job manipulation and must be protected. Unauthorized modification of the at.deny file could result in Denial of Service to authorized "at" users or provide unauthorized users with the ability to run "at" jobs. | Check the permissions of the file. # ls -lL /etc/at.deny If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/at.deny |
| V-22394 | CCI-000225 | medium | The cron.deny file must be group-owned by root, bin, sys, or cron. | Cron daemon control files restrict the scheduling of automated tasks and must be protected. Unauthorized modification of the cron.deny file could result in Denial of Service to authorized cron users or could provide unauthorized users with the ability to run cron jobs. | Check the group ownership of the file. Procedure: # ls -lL /etc/cron.deny If the file is not group-owned by root, bin, sys, this is a finding. | Change the group ownership of the file. # chgrp root /etc/cron.deny |
| V-22395 | CCI-000225 | medium | The "at" directory must not have an extended ACL. | If the "at" directory has an extended ACL, unauthorized users could be allowed to view or to edit files containing sensitive information within the "at" directory. Unauthorized modifications could result in Denial of Service to authorized "at" jobs. | Check the permissions of the directory. # ls -lLd /var/spool/at If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the directory. # setfacl --remove-all /var/spool/at |
| V-22396 | CCI-000225 | medium | The "at" directory must be group-owned by root, bin, sys, or cron. | If the group of the "at" directory is not root, bin, sys, or cron, unauthorized users could be allowed to view or edit files containing sensitive information within the directory. | Check the group ownership of the file. Procedure: # ls -lL /var/spool/at If the file is not group-owned by root, bin, sys, daemon or cron, this is a finding. | Change the group ownership of the file to root, bin, sys, daemon or cron. Procedure: # chgrp <root or other system group> <"at" directory> |
| V-22397 | CCI-000225 | medium | The at.allow file must be group-owned by root, bin, sys, or cron. | If the group owner of the at.allow file is not set to root, bin, sys, or cron, unauthorized users could be allowed to view or edit the list of users permitted to run "at" jobs. Unauthorized modification could result in Denial of Service to authorized "at" users or provide unauthorized users with the ability to run "at" jobs. | Check the group ownership of the file. Procedure: # ls -lL /etc/at.allow If the file is not group-owned by root, bin, sys, or cron, this is a finding. | Change the group ownership of the file. Procedure: # chgrp root /etc/at.allow |
| V-22398 | CCI-000225 | medium | The at.deny file must be group-owned by root, bin, sys, or cron. | If the group owner of the at.deny file is not set to root, bin, sys, or cron, unauthorized users could be allowed to view or edit sensitive information contained within the file. Unauthorized modification could result in Denial of Service to authorized "at" users or provide unauthorized users with the ability to run "at" jobs. | Check the group ownership of the file. Procedure: # ls -lL /etc/at.deny If the file is not group-owned by root, bin, sys, or cron, this is a finding. | Change the group ownership of the at.deny file to root, sys, bin, or cron. Procedure: # chgrp root /etc/at.deny |
| V-22404 | CCI-000366 | medium | Kernel core dumps must be disabled unless needed. | Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps may consume a considerable amount of disk space and may result in Denial of Service by exhausting the available space on the target file system. The kernel core dump process may increase the amount of time a system is unavailable due to a crash. Kernel core dumps can be useful for kernel debugging. | Verify the kdump service is not running. Procedure: # service kdump status If "Kdump is operational" is returned, this is a finding. | Disable kdump. # service kdump stop # chkconfig kdump off |
| V-22405 | CCI-000225 | low | The kernel core dump data directory must be group-owned by root, bin, sys, or system. | Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the kernel core dump data directory is not group-owned by a system group, the core dumps contained in the directory may be subject to unauthorized access. | Determine the kernel core dump data directory and check its ownership. Procedure: Examine /etc/kdump.conf. The "path" parameter, which defaults to /var/crash, determines the path relative to the crash dump device. The crash device is specified with a filesystem type and device, such as "ext3 /dev/sda2". Using this information, determine where this path is currently mounted on the system. # ls -ld <kernel dump data directory> If the directory is not group-owned by root, bin, sys, or system, this is a finding. | Change the group-owner of the kernel core dump data directory. # chgrp root <kernel core dump data directory> |
| V-22406 | CCI-000225 | low | The kernel core dump data directory must have mode 0700 or less permissive. | Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If the mode of the kernel core dump data directory is more permissive than 0700, unauthorized users may be able to view or to modify kernel core dump data files. | Determine the kernel core dump data directory and check its permissions. Procedure: Examine /etc/kdump.conf. The "path" parameter, which defaults to /var/crash, determines the path relative to the crash dump device. The crash device is specified with a filesystem type and device, such as "ext3 /dev/sda2". Using this information, determine where this path is currently mounted on the system. # ls -l <kernel dump directory> If the directory has a mode more permissive than 0700, this is a finding. | Change the group-owner of the kernel core dump data directory. # chmod 0700 <kernel core dump data directory> |
| V-22407 | CCI-000225 | low | The kernel core dump data directory must not have an extended ACL. | Kernel core dumps may contain the full contents of system memory at the time of the crash. As the system memory may contain sensitive information, it must be protected accordingly. If there is an extended ACL for the kernel core dump data directory, unauthorized users may be able to view or to modify kernel core dump data files. | Determine the kernel core dump data directory and check its permissions. Procedure: Examine /etc/kdump.conf. The "path" parameter, which defaults to /var/crash, determines the path relative to the crash dump device. The crash device is specified with a filesystem type and device, such as "ext3 /dev/sda2". Using this information, determine where this path is currently mounted on the system. # ls -l <kernel dump directory> If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all <core file directory> |
| V-22408 | CCI-000225 | medium | Network interfaces must not be configured to allow user control. | Configuration of network interfaces should be limited to privileged users. Manipulation of network interfaces may result in a Denial of Service or bypass of network security mechanisms. | Check the system for user-controlled network interfaces. # grep -l '^USERCTL=yes' /etc/sysconfig/network-scripts/ifcfg* If any results are returned, this is a finding. | Edit the configuration for the user-controlled interface and remove the "USERCTL=yes" configuration line or set to "USERCTL=no". |
| V-22409 | CCI-001551 | low | The system must not process Internet Control Message Protocol (ICMP) timestamp requests. | The processing of (ICMP) timestamp requests increases the attack surface of the system. | Verify the system does not respond to ICMP TIMESTAMP_REQUESTs Procedure: # grep "timestamp" /etc/sysconfig/iptables This should return entries for "timestamp-reply" and "timestamp_request". Both should end with "-j DROP'. If either does not exist or does not "DROP" the message, this is a finding. | Configure the system to not respond to ICMP TIMESTAMP_REQUESTs. This is done by rejecting ICMP type 13 and 14 messages at the firewall. Procedure: Edit /etc/sysconfig/iptables to add: -A RH-Firewall-1-INPUT -p ICMP --icmp-type timestamp-request -j DROP -A RH-Firewall-1-INPUT -p ICMP --icmp-type timestamp-reply -j DROP Restart the firewall: # service iptables restart |
| V-22410 | CCI-001551 | medium | The system must not respond to Internet Control Message Protocol v4 (ICMPv4) echoes sent to a broadcast address. | Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks. | Verify the system does not respond to ICMP ECHO_REQUESTs set to broadcast addresses. Procedure: # cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts If the result is not 1, this is a finding. | Configure the system to not respond to ICMP ECHO_REQUESTs sent to broadcast addresses. Edit /etc/sysctl.conf and add a setting for "net.ipv4.icmp_echo_ignore_broadcasts=1" and reload the sysctls. Procedure: # echo "net.ipv4.icmp_echo_ignore_broadcasts=1" >> /etc/sysctl.conf # sysctl -p |
| V-22411 | CCI-001551 | medium | The system must not respond to Internet Control Message Protocol (ICMP) timestamp requests sent to a broadcast address. | The processing of (ICMP) timestamp requests increases the attack surface of the system. Responding to broadcast ICMP timestamp requests facilitates network mapping and provides a vector for amplification attacks. | Verify the system does not respond to ICMP TIMESTAMP_REQUESTs set to broadcast addresses. Procedure: # cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts If the result is not 1, this is a finding. Note: The same parameter controls both ICMP ECHO_REQUESTs and TIMESTAMP_REQUESTs. | Configure the system to not respond to ICMP TIMESTAMP_REQUESTs sent to broadcast addresses. Edit /etc/sysctl.conf and add a setting for "net.ipv4.icmp_echo_ignore_broadcasts=1" and reload the sysctls. Procedure: # echo "net.ipv4.icmp_echo_ignore_broadcasts=1" >> /etc/sysctl.conf # sysctl -p |
| V-22414 | CCI-001551 | medium | The system must not accept source-routed IPv4 packets. | Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the handling of source-routed traffic destined to the system itself, not to traffic forwarded by the system to another system, such as when IPv4 forwarding is enabled and the system is functioning as a router. | Verify the system does not accept source-routed IPv4 packets. Procedure: # grep [01] /proc/sys/net/ipv4/conf/*/accept_source_route|egrep "default|all" If all of the resulting lines do not end with "0", this is a finding. | Configure the system to not accept source-routed IPv4 packets. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.accept_source_route=0" and "net.ipv4.conf.default.accept_source_route=0". Reload the sysctls. Procedure: # sysctl -p |
| V-22415 | CCI-001551 | medium | Proxy Address Resolution Protocol (Proxy ARP) must not be enabled on the system. | Proxy ARP allows a system to respond to ARP requests on one interface on behalf of hosts connected to another interface. If this function is enabled when not required, addressing information may be leaked between the attached network segments. | Verify the system does not use proxy ARP. # grep [01] /proc/sys/net/ipv4/conf/*/proxy_arp|egrep "default|all" If all of the resulting lines do not end with "0", this is a finding. | Configure the system to not use proxy ARP. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.proxy_arp=0" and "net.ipv4.conf.default.proxy_arp=0". # sysctl -p |
| V-22416 | CCI-001503 | medium | The system must ignore IPv4 Internet Control Message Protocol (ICMP) redirect messages. | ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. | Verify the system does not accept IPv4 ICMP redirect messages. # grep [01] /proc/sys/net/ipv4/conf/*/accept_redirects|egrep "default|all" If all of the resulting lines do not end with "0", this is a finding. | Configure the system to not accept IPv4 ICMP redirect messages. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.accept_redirects=0" and "net.ipv4.conf.default.accept_redirects=0". # sysctl -p |
| V-22417 | CCI-001551 | medium | The system must not send IPv4 Internet Control Message Protocol (ICMP) redirects. | ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology. | Verify the system does not send IPv4 ICMP redirect messages. # grep [01] /proc/sys/net/ipv4/conf/*/send_redirects|egrep "default|all" If all of the resulting lines do not end with "0", this is a finding. | Configure the system to not send IPv4 ICMP redirect messages. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.send_redirects=0" and "net.ipv4.conf.default.send_redirects=0". # sysctl -p |
| V-22418 | CCI-000126 | low | The system must log martian packets. | Martian packets are packets containing addresses known by the system to be invalid. Logging these messages allows the SA to identify misconfigurations or attacks in progress. | Verify the system logs martian packets. # grep [01] /proc/sys/net/ipv4/conf/*/log_martians|egrep "default|all" If all of the resulting lines do not end with "1", this is a finding. | Configure the system to log martian packets. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.log_martians=1" and "net.ipv4.conf.default.log_martians=1". Reload the sysctls. Procedure: # sysctl -p |
| V-22419 | CCI-001092 | medium | The system must be configured to use TCP syncookies when experiencing a TCP SYN flood. | A TCP SYN flood attack can cause Denial of Service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies are a mechanism used to only track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This technique does not operate in a fully standards-compliant manner, but is only activated when a flood condition is detected, and allows defense of the system while continuing to service valid requests. | Verify the system configured to use TCP syncookies when experiencing a TCP SYN flood. # cat /proc/sys/net/ipv4/tcp_syncookies If the result is not "1", this is a finding. | Configure the system to use TCP syncookies when experiencing a TCP SYN flood. Edit /etc/sysctl.conf and add a setting for "net.ipv4.tcp_syncookies=1". # sysctl -p |
| V-22421 | CCI-001551 | medium | The system must not be configured for network bridging. | Some systems have the ability to bridge or switch frames (link-layer forwarding) between multiple interfaces. This can be useful in a variety of situations but, if enabled when not needed, has the potential to bypass network partitioning and security. | Verify the system is not configured for bridging. # ls /proc/sys/net/bridge If the directory exists, this is a finding. # lsmod | grep '^bridge ' If any results are returned, this is a finding. Fix Text: Configure the system to not use bridging. | Configure the system to not use bridging. # rmmod bridge Edit /etc/modprobe.conf and add a line such as "install bridge /bin/false" to prevent the loading of the bridge module. |
| V-22422 | CCI-000553 | low | All local file systems must employ journaling or another mechanism ensuring file system consistency. | File system journaling, or logging, can allow reconstruction of file system data after a system crash preserving the integrity of data that may have otherwise been lost. Journaling file systems typically do not require consistency checks upon booting after a crash, which can improve system availability. Some file systems employ other mechanisms to ensure consistency also satisfying this requirement. | Verify local filesystems use journaling. # mount | grep '^/dev/' | egrep -v 'type (ext3|ext4|jfs|reiserfs|xfs|iso9660|udf)' If a mount is listed, this is a finding. | Convert local file systems to use journaling or another mechanism ensuring file system consistency. |
| V-22423 | CCI-000225 | medium | The inetd.conf file, xinetd.conf file, and the xinetd.d directory must be group-owned by root, bin, sys, or system. | Failure to give ownership of sensitive files or utilities to system groups may provide unauthorized users with the potential to access sensitive information or change the system configuration possibly weakening the system's security posture. | Check the group ownership of the xinetd configuration files and directories. Procedure: # ls -alL /etc/xinetd.conf /etc/xinetd.d If a file or directory is not group-owned by root, bin, sys, or system, this is a finding. | Change the group-owner of the xinetd configuration files and directories. Procedure: # chgrp -R root /etc/xinetd.conf /etc/xinetd.d |
| V-22424 | CCI-000225 | medium | The inetd.conf and xinetd.conf files must not have extended ACLs. | The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system. | Check the permissions of the xinetd configuration files. Procedure: # ls -alL /etc/xinetd.conf If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/xinetd.conf |
| V-22425 | CCI-000225 | medium | The xinetd.d directory must have mode 0755 or less permissive. | The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system. | Check the permissions of the xinetd configuration directories. # ls -dlL /etc/xinetd.d If the mode of the directory is more permissive than 0755, this is a finding. | Change the mode of the directory. # chmod 0755 /etc/xinetd.d |
| V-22426 | CCI-000225 | medium | The xinetd.d directory must not have an extended ACL. | The Internet service daemon configuration files must be protected as malicious modification could cause Denial of Service or increase the attack surface of the system. | Check the permissions of the xinetd configuration files and directories. # ls -alL /etc/xinetd.conf /etc/xinetd.d If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/xinetd.d |
| V-22427 | CCI-000225 | medium | The services file must be group-owned by root, bin, sys, or system. | Failure to give ownership of system configuration files to root or a system group provides the designated owner and unauthorized users with the potential to change the system configuration possibly weakening the system's security posture. | Check the group ownership of the services file. Procedure: # ls -lL /etc/services If the file is not group-owned by root, bin, sys, or system, this is a finding | Change the group-owner of the services file. Procedure: # chgrp root /etc/services |
| V-22428 | CCI-000225 | medium | The services file must not have an extended ACL. | The services file is critical to the proper operation of network services and must be protected from unauthorized modification. If the services file has an extended ACL, it may be possible for unauthorized users to modify the file. Unauthorized modification could result in the failure of network services. | Check the permissions of the /etc/services file. # ls -lL /etc/services If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/services |
| V-22429 | CCI-001436 | medium | The portmap or rpcbind service must not be running unless needed. | The portmap and rpcbind services increase the attack surface of the system and should only be used when needed. The portmap or rpcbind services are used by a variety of services using Remote Procedure Calls (RPCs). | Check the status of the portmap service. # service portmap status If the service is running, this is a finding. | Shutdown and disable the portmap service. # service portmap stop; chkconfig portmap off |
| V-22430 | CCI-000305 | medium | The portmap or rpcbind service must not be installed unless needed. | The portmap and rpcbind services increase the attack surface of the system and should only be used when needed. The portmap or rpcbind services are used by a variety of services using Remote Procedure Calls (RPCs). | Check if the portmap package is installed. # rpm -qa | grep portmap If a package is found, this is a finding. | Remove the portmap package. # rpm -e portmap or # yum remove portmap |
| V-22431 | CCI-000305 | medium | The rshd service must not be installed. | The rshd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service. | Check if the rsh-server package is installed. Procedure: # rpm -qa | grep rsh-server If a package is found, this is a finding. | Remove the rsh-server package. Procedure: # rpm -e rsh-server |
| V-22432 | CCI-000068 | medium | The rlogind service must not be running. | The rlogind process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service. | Check the rlogind configuration. # cat /etc/xinetd.d/rlogin If the file exists and does not contain "disable = yes" this is a finding. | Remove or disable the rlogin configuration and restart xinetd. # rm /etc/xinetd.d/rlogin ; service xinetd restart |
| V-22433 | CCI-000305 | medium | The rlogind service must not be installed. | The rlogind process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service. | Check if the rsh-server package is installed. Procedure: # rpm -qa | grep rsh-server If a package is found, this is a finding. | Remove the rsh-server package. Procedure: # rpm -e rsh-server |
| V-22434 | CCI-000305 | medium | The rexecd service must not be installed. | The rexecd process provides a typically unencrypted, host-authenticated remote access service. SSH should be used in place of this service. | Check if the rsh-server package is installed. Procedure: # rpm -qa | grep rsh-server If a package is found, this is a finding. | Remove the rsh-server package. Procedure: # rpm -e rsh-server |
| V-22435 | CCI-000225 | medium | The hosts.lpd (or equivalent) file must be group-owned by root, bin, sys, or system. | Failure to give group-ownership of the hosts.lpd file to root, bin, sys, or system provides the members of the owning group and possible unauthorized users, with the potential to modify the hosts.lpd file. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers. | Check the group ownership of the /etc/cups/printers.conf file. Procedure: # ls -lL /etc/cups/printers.conf If the file is not group-owned by lp, this is a finding. | Change the group-owner of the printers.conf file. Procedure: # chgrp lp /etc/cups/printers.conf |
| V-22436 | CCI-000225 | medium | The hosts.lpd (or equivalent) file must not have an extended ACL. | Excessive permissions on the hosts.lpd (or equivalent) file may permit unauthorized modification. Unauthorized modifications could disrupt access to local printers from authorized remote hosts or permit unauthorized remote access to local printers. | Check the permissions of the /etc/cups/printers.conf file. # ls -lL /etc/cups/printers.conf If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/cups/printers.conf |
| V-22437 | CCI-000225 | medium | The traceroute file must not have an extended ACL. | If an extended ACL exists on the traceroute executable file, it may provide unauthorized users with access to the file. Malicious code could be inserted by an attacker and triggered whenever the traceroute command is executed by authorized users. Additionally, if an unauthorized user is granted executable permissions to the traceroute command, it could be used to gain information about the network topology behind the firewall. This information may allow an attacker to determine trusted routers and other network information potentially leading to system and network compromise. | Check the permissions of the /bin/traceroute file. # ls -lL /bin/traceroute If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /bin/traceroute |
| V-22438 | CCI-000225 | medium | The aliases file must be group-owned by root, sys, bin, or system. | If the alias file is not group-owned by root or a system group, an unauthorized user may modify the file adding aliases to run malicious code or redirect e-mail. | Check the group ownership of the alias files. Procedure: for sendmail: # ls -lL /etc/aliases If the files are not group-owned by root, this is a finding. # ls -lL /etc/aliases.db If the file is not group-owned by the same system group as sendmail, which is smmsp by default, this is a finding. for postfix: Verify the location of the alias file. # postconf alias maps This will return the location of the "aliases" file, by default "/etc/postfix/aliases" # ls -lL <postfix aliases file> If the files are not group-owned by root, this is a finding. # ls -lL <postfix aliases.db file> If the file is not group-owned by root, this is a finding. | Change the group-owner of the /etc/aliases file. Procedure: for sendmail: # chgrp root /etc/aliases # chgrp smmsp /etc/aliases.db The aliases.db file must be owned by the same system group as sendmail, which is smmsp by default. for postfix # chgrp root /etc/postfix/aliases # chgrp root /etc/postfix/aliases.db |
| V-22439 | CCI-000225 | medium | The alias file must not have an extended ACL. | Excessive permissions on the aliases file may permit unauthorized modification. If the alias file is modified by an unauthorized user, they may modify the file to run malicious code or redirect e-mail. | Check the permissions of the alias file. Procedure: for sendmail: # ls -lL /etc/aliases /etc/aliases.db If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. for postfix: Verify the location of the alias file. # postconf alias maps This will return the location of the "aliases" file, by default "/etc/postfix/aliases" # ls -lL <postfix aliases file> <postfix aliases.db file> If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended permissions from the alias files. Procedure: for sendmail: # setfacl --remove-all /etc/aliases /etc/aliases.db for postfix (assuming the default postfix directory): # setfacl --remove-all /etc/postfix/aliases /etc/postfix/aliases.db |
| V-22440 | CCI-000225 | medium | Files executed through a mail aliases file must be group-owned by root, bin, sys, or system, and must reside within a directory group-owned by root, bin, sys, or system. | If a file executed through a mail aliases file is not group-owned by root or a system group, it may be subject to unauthorized modification. Unauthorized modification of files executed through aliases may allow unauthorized users to attain root privileges. | Examine the contents of the /etc/aliases file. Procedure: # more /etc/aliases Examine the aliases file for any utilized directories or paths. # ls -lL <file referenced from aliases> Check the permissions for any paths referenced. If the group owner of any file is not root, bin, sys, or system, this is a finding. | Change the group ownership of the file referenced from /etc/aliases. Procedure: # chgrp root <file referenced from aliases> |
| V-22441 | CCI-000225 | medium | Files executed through a mail aliases file must not have extended ACLs. | Excessive permissions on files executed through a mail aliases file could result in modification by an unauthorized user, execution of malicious code, and/or system compromise. | Examine the contents of the /etc/aliases file. Procedure: # more /etc/aliases Examine the aliases file for any utilized directories or paths. # ls -lL <file referenced from aliases> Check the permissions for any paths referenced. If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all <file referenced from aliases> |
| V-22442 | CCI-000225 | medium | The SMTP service log file must not have an extended ACL. | If the SMTP service log file has an extended ACL, unauthorized users may be allowed to access or to modify the log file. | Examine /etc/syslog.conf and determine the log file(s) receiving logs for "mail.crit", "mail.debug", mail.*, or "*.crit". Procedure: This check is applicable to both Postfix or sendmail servers. Check the permissions on these log files.Identify any log files configured for "*.crit" and the "mail" service (excluding mail.none) and at any severity level. # egrep "(\*.crit|mail\.[^n][^/]*)" /etc/syslog.conf|sed 's/^[^/]*//'|xargs ls -lL If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | This fix is applicable to both Postfix and sendmail servers. Remove the extended ACL from the file. # setfacl --remove-all <log file> |
| V-22444 | CCI-000225 | medium | The ftpusers file must be group-owned by root, bin, sys, or system. | If the ftpusers file is not group-owned by root or a system group, an unauthorized user may modify the file to allow unauthorized accounts to use FTP. | Check the group ownership of the ftpusers file. Procedure: # ls -lL /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers If the file is not group-owned by root, bin, sys, or system, this is a finding. | Change the group owner of the ftpusers file. Procedure: # chgrp root /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers |
| V-22445 | CCI-000225 | medium | The ftpusers file must not have an extended ACL. | Excessive permissions on the ftpusers file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized users to access the FTP service. | Check the permissions of the /etc/ftpusers file. # ls -lL /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers |
| V-22446 | CCI-000225 | medium | The .Xauthority files must not have extended ACLs. | .Xauthority files ensure the user is authorized to access specific X Windows host. Extended ACLs may permit unauthorized modification of these files, which could lead to Denial of Service to authorized access or allow unauthorized access to be obtained. | Check the file permissions for the .Xauthority files. These files will be located in user home directories. Procedure: # ls -la ~username |egrep "(\.Xauthority|\.xauth)" If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all .Xauthority |
| V-22447 | CCI-001435 | medium | The SNMP service must use only SNMPv3 or its successors. | SNMP Versions 1 and 2 are not considered secure. Without the strong authentication and privacy provided by the SNMP Version 3 User-based Security Model (USM), an attacker or other unauthorized users may gain access to detailed system management information and use the information to launch attacks against the system. | Check the SNMP daemon is not configured to use the v1 or v2c security models. Procedure: Examine the default install location /etc/snmpd.conf or: # find / -name snmpd.conf # grep -E '(v1|v2c|community|com2sec)' <snmp.conf file> | grep -v '^#' If any configuration is found, this is a finding. | Edit /etc/snmpd.conf and remove references to the "v1", "v2c", "community", or "com2sec". Restart the SNMP service. # service snmpd restart |
| V-22448 | CCI-001453 | medium | The SNMP service must require the use of a FIPS 140-2 approved cryptographic hash algorithm as part of its authentication and integrity methods. | The SNMP service must use SHA-1 or a FIPS 140-2 approved successor for authentication and integrity. | Verify the SNMP daemon uses SHA for SNMPv3 users. Procedure: Examine the default install location /etc/snmp/snmpd.conf or: # find / -name snmpd.conf # grep -v '^#' <snmpd.conf file> | grep -i createuser | grep -vi SHA If any line is present this is a finding. | Edit /etc/snmp/snmpd.conf and add the SHA keyword for any create user statement without one. Restart the SNMP service. # service snmpd restart |
| V-22449 | CCI-000068 | medium | The SNMP service must require the use of a FIPS 140-2 approved encryption algorithm for protecting the privacy of SNMP messages. | The SNMP service must use AES or a FIPS 140-2 approved successor algorithm for protecting the privacy of communications. | Verify the SNMP daemon uses AES for SNMPv3 users. Procedure: Examine the default install location /etc/snmp/snmpd.conf or: # find / -name snmpd.conf # grep -v '^#' <snmpd.conf file> | grep -i createuser | grep -vi AES If any line is present this is a finding. | Edit /etc/snmp/snmpd.conf and add the AES keyword for any create user statement without one. Restart the SNMP service. # service snmpd restart |
| V-22450 | CCI-000225 | medium | Management Information Base (MIB) files must not have extended ACLs. | The ability to read the MIB file could impart special knowledge to an intruder or malicious user about the ability to extract compromising information about the system or network. | Check the file permissions for the MIB files. # find / -name *.mib # ls -lL <mib file> If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all <mib file> |
| V-22451 | CCI-000225 | medium | The snmpd.conf file must be group-owned by root, bin, sys, or system. | The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification. If the file is not group-owned by a system group, it may be subject to access and modification from unauthorized users. | Check the group ownership of the SNMP configuration file. Procedure: Examine the default install location /etc/snmp/snmpd.conf or: # find / -name snmpd.conf # ls -lL <snmpd.conf> If the file is not group-owned by root, bin, sys, or system, this is a finding. | Change the group ownership of the SNMP configuration file. Procedure: # chgrp root <snmpd.conf> |
| V-22452 | CCI-000225 | medium | The snmpd.conf file must not have an extended ACL. | The snmpd.conf file contains authenticators and must be protected from unauthorized access and modification. | Check the permissions of the SNMP configuration file. Procedure: Examine the default install location /etc/snmp/snmpd.conf or: # find / -name snmpd.conf # ls -lL <snmpd.conf> If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all <snmpd.conf file> |
| V-22453 | CCI-000225 | medium | The /etc/syslog.conf file must have mode 0640 or less permissive. | Unauthorized users must not be allowed to access or modify the /etc/syslog.conf file. | Check the permissions of the syslog configuration file. # ls -lL /etc/syslog.conf If the mode of the file is more permissive than 0640, this is a finding. | Change the permissions of the syslog configuration file. # chmod 0640 /etc/syslog.conf |
| V-22454 | CCI-000225 | medium | The /etc/syslog.conf file must not have an extended ACL. | Unauthorized users must not be allowed to access or modify the /etc/syslog.conf file. | Check the permissions of the syslog configuration file. # ls -lL /etc/syslog.conf If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/syslog.conf |
| V-22455 | CCI-000136 | medium | The system must use a remote syslog server (loghost). | A syslog server (loghost) receives syslog messages from one or more systems. This data can be used as an authoritative log source in the event a system is compromised and its local logs are suspect. | Check the syslog configuration file for remote syslog servers. # grep '@' /etc/syslog.conf | grep -v '^#' If no line is returned, this is a finding. | Edit the syslog configuration file and add an appropriate remote syslog server. |
| V-22456 | CCI-001436 | medium | The SSH client must be configured to only use the SSHv2 protocol. | SSHv1 is not a DoD-approved protocol and has many well-known vulnerability exploits. Exploits of the SSH client could provide access to the system with the privileges of the user running the client. | Check the SSH client configuration for allowed protocol versions. # grep -i protocol /etc/ssh/ssh_config | grep -v '^#' If the returned protocol configuration allows versions less than 2, this is a finding. | Edit the /etc/ssh/ssh_config file and add or edit a "Protocol" configuration line not allowing versions less than 2. |
| V-22457 | CCI-000069 | medium | The SSH daemon must only listen on management network addresses unless authorized for uses other than management. | The SSH daemon should only listen on network addresses designated for management traffic. If the system has multiple network interfaces and SSH listens on addresses not designated for management traffic, the SSH service could be subject to unauthorized access. If SSH is used for purposes other than management, such as providing an SFTP service, the list of approved listening addresses may be documented. | Ask the SA to identify which interfaces on the system are designated for management traffic. If all interfaces on the system are authorized for management traffic, this is not applicable. Check the SSH daemon configuration for listening network addresses. # grep -i Listen /etc/ssh/sshd_config | grep -v '^#' If no configuration is returned, or if a returned 'Listen' configuration contains addresses not designated for management traffic, this is a finding. | Edit the SSH daemon configuration to specify listening network addresses designated for management traffic. |
| V-22458 | CCI-000068 | medium | The SSH daemon must be configured to only use FIPS 140-2 approved ciphers. | DoD information systems are required to use FIPS 140-2 approved ciphers. SSHv2 ciphers meeting this requirement are 3DES and AES. | Check the SSH daemon configuration for allowed ciphers. # grep -i ciphers /etc/ssh/sshd_config | grep -v '^#' If no lines are returned, or the returned ciphers list contains any cipher not starting with "3des" or "aes", this is a finding | Edit the SSH daemon configuration and remove any ciphers not starting with with "3des" or "aes" and remove any ciphers ending with "cbc". If necessary, add a "Ciphers" line. |
| V-22459 | CCI-000366 | medium | The SSH daemon must be configured to not use Cipher-Block Chaining (CBC) ciphers. | The Cipher-Block Chaining (CBC) mode of encryption as implemented in the SSHv2 protocol is vulnerable to chosen plain text attacks and must not be used. | Check the SSH daemon configuration for allowed ciphers. # grep -i ciphers /etc/ssh/sshd_config | grep -v '^#' If no lines are returned, or the returned ciphers list contains any cipher ending with cbc, this is a finding. | Edit /etc/ssh/sshd_config and add or edit the "Ciphers" line. Only include ciphers that start with "3des" or "aes" and do not contain "cbc". For the list of available ciphers for the particular version of your software, consult the sshd_config manpage. |
| V-22460 | CCI-001453 | medium | The SSH daemon must be configured to only use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hash algorithms. | DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions. | Check the SSH daemon configuration for allowed MACs. Procedure: # grep -i macs /etc/ssh/sshd_config | grep -v '^#' If no lines are returned, or the returned MACs list contains any MAC other than "hmac-sha1", this is a finding. | Edit the SSH daemon configuration and remove any MACs other than "hmac-sha1". If necessary, add a "MACs" line. |
| V-22461 | CCI-000068 | medium | The SSH client must be configured to only use FIPS 140-2 approved ciphers. | DoD information systems are required to use FIPS 140-2 approved ciphers. SSHv2 ciphers meeting this requirement are 3DES and AES. | Check the SSH client configuration for allowed ciphers. # grep -i ciphers /etc/ssh/ssh_config | grep -v '^#' If no lines are returned, or the returned ciphers list contains any cipher not starting with "3des" or "aes", this is a finding. | Edit the SSH client configuration and remove any ciphers not starting with with "3des" or "aes" and remove any ciphers ending with "cbc". If necessary, add a "Ciphers" line. |
| V-22462 | CCI-000366 | medium | The SSH client must be configured to not use Cipher-Block Chaining (CBC)-based ciphers. | The (CBC) mode of encryption as implemented in the SSHv2 protocol is vulnerable to chosen-plaintext attacks and must not be used. | Check the SSH client configuration for allowed ciphers. # grep -i ciphers /etc/ssh/ssh_config | grep -v '^#' If no lines are returned, or the returned ciphers list contains any cipher ending with "cbc", this is a finding. | Edit the SSH client configuration and remove any ciphers not starting with with "3des" or "aes" and remove any ciphers ending with "cbc". If necessary, add a "Ciphers" line. |
| V-22463 | CCI-001453 | medium | The SSH client must be configured to only use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hash algorithms. | DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions. | Check the SSH client configuration for allowed MACs. # grep -i macs /etc/ssh/ssh_config | grep -v '^#' If no lines are returned, or the returned MACs list contains any MAC other than "hmac-sha1", this is a finding. | Edit the SSH client configuration and remove any MACs other than "hmac-sha1". If necessary, add a "MACs" line. |
| V-22470 | CCI-000225 | medium | The SSH daemon must restrict login ability to specific users and/or groups. | Restricting SSH logins to a limited group of users, such as system administrators, prevents password-guessing and other SSH attacks from reaching system accounts and other accounts not authorized for SSH access. | There are two ways in which access to SSH may restrict users or groups. Check if /etc/pam.d/sshd is configured to require daemon style login control. # grep pam_access.so /etc/pam.d/sshd|grep "required"|grep "account"| grep -v '^#' If no lines are returned, sshd is not configured to use pam_access. Check the SSH daemon configuration for the AllowGroups setting. # egrep -i "AllowGroups|AllowUsers" /etc/ssh/sshd_config | grep -v '^#' If no lines are returned, sshd is not configured to limit access to users/groups. If sshd is not configured to limit access either through pam_access or the use "AllowUsers" or "Allowgroups", this is a finding. | Edit the SSH daemon configuration and add an "AllowGroups" or "AllowUsers" directive specifying the groups and users allowed to have access. Alternatively, modify the /etc/pam.d/sshd file to include the line account required pam_access.so accessfile=<path to access.conf for sshd> If the "accessfile" option is not specified the default "access.conf" file will be used. The "access.conf" file must contain the user restriction definitions. |
| V-22471 | CCI-000225 | medium | The SSH public host key files must have mode 0644 or less permissive. | If a public host key file is modified by an unauthorized user, the SSH service may be compromised. | Check the permissions for SSH public host key files. # ls -lL /etc/ssh/*key.pub If any file has a mode more permissive than 0644, this is a finding. | Change the permissions for the SSH public host key files. # chmod 0644 /etc/ssh/*key.pub |
| V-22472 | CCI-000225 | medium | The SSH private host key files must have mode 0600 or less permissive. | If an unauthorized user obtains the private SSH host key file, the host could be impersonated. | Check the permissions for SSH private host key files. # ls -lL /etc/ssh/*key If any file has a mode more permissive than 0600, this is a finding. | Change the permissions for the SSH private host key files. # chmod 0600 /etc/ssh/*key |
| V-22473 | CCI-000366 | low | The SSH daemon must not permit GSSAPI authentication unless needed. | GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system’s GSSAPI to remote hosts, increasing the attack surface of the system. GSSAPI authentication must be disabled unless needed. | Ask the SA if GSSAPI authentication is used for SSH authentication to the system. If so, this is not applicable. Check the SSH daemon configuration for the GSSAPIAuthentication setting. # grep -i GSSAPIAuthentication /etc/ssh/sshd_config | grep -v '^#' If no lines are returned, or the setting is set to "yes", this is a finding. | Edit the SSH daemon configuration and set (add if necessary) a "GSSAPIAuthentication" directive set to "no". |
| V-22474 | CCI-000366 | low | The SSH client must not permit GSSAPI authentication unless needed. | GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system’s GSSAPI to remote hosts, increasing the attack surface of the system. GSSAPI authentication must be disabled unless needed. | The default setting for GSSAPIAuthentication is "no" . Check for a change from the default. # grep -i GSSAPIAuthentication /etc/ssh/ssh_config | grep -v '^#' If the setting is "yes" this is a finding. | Edit the SSH client configuration and set the GSSAPIAuthentication" directive set to "no". |
| V-22475 | CCI-000366 | low | The SSH daemon must not permit Kerberos authentication unless needed. | Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementation may then be subject to exploitation. To reduce the attack surface of the system, the Kerberos authentication mechanism within SSH must be disabled for systems not using this capability. | Ask the SA if Kerberos authentication is used by the system. If it is, this is not applicable. Check the SSH daemon configuration for the KerberosAuthentication setting. # grep -i KerberosAuthentication /etc/ssh/sshd_config | grep -v '^#' If no lines are returned, or the setting is set to "yes", this is a finding. | Edit the SSH daemon configuration and set (add if necessary) the "KerberosAuthentication" directive set to "no". |
| V-22485 | CCI-000225 | medium | The SSH daemon must perform strict mode checking of home directory configuration files. | If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user. | Check the SSH daemon configuration for the StrictModes setting. # grep -i StrictModes /etc/ssh/sshd_config | grep -v '^#' If the setting is not present, or not set to "yes", this is a finding. | Edit the SSH daemon configuration and add or edit the "StrictModes" setting value to "yes". |
| V-22486 | CCI-000225 | medium | The SSH daemon must use privilege separation. | SSH daemon privilege separation causes the SSH process to drop root privileges when not needed, which would decrease the impact of software vulnerabilities in the unprivileged section. | Check the SSH daemon configuration for the UsePrivilegeSeparation setting. # grep -i UsePrivilegeSeparation /etc/ssh/sshd_config | grep -v '^#' If the setting is not present, or not set to "yes", this is a finding. | Edit the SSH daemon configuration and add or edit the "UsePrivilegeSeparation" setting value to "yes". |
| V-22487 | CCI-000366 | medium | The SSH daemon must not allow rhosts RSA authentication. | If SSH permits rhosts RSA authentication, a user may be able to log in based on the keys of the host originating the request and not any user-specific authentication. | Check the SSH daemon configuration for the RhostsRSAAuthentication setting. # grep -i RhostsRSAAuthentication /etc/ssh/sshd_config | grep -v '^#' If the setting is set to "yes", this is a finding. | Edit the SSH daemon configuration and add or edit the "RhostsRSAAuthentication" setting value to "no". |
| V-22488 | CCI-000366 | medium | The SSH daemon must not allow compression or must only allow compression after successful authentication. | If compression is allowed in an SSH connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection, potentially with root privileges. | Check the SSH daemon configuration for the compression setting. # grep -i Compression /etc/ssh/sshd_config | egrep "no|delayed" If the setting is missing or is commented out, this is a finding. If the setting is present but is not set to "no" or "delayed", this is a finding. | Edit the SSH daemon configuration and add or edit the "Compression" setting value to "no" or "delayed". |
| V-22489 | CCI-000048 | medium | The SSH daemon must be configured with the Department of Defense (DoD) logon banner. | Failure to display the DoD logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources. The SSH service must be configured to display the DoD logon warning banner either through the SSH configuration or a wrapper program such as TCP_WRAPPERS. The SSH daemon may also be used to provide SFTP service. The warning banner configuration for SSH will apply to SFTP. | Verify the SSH daemon is configured for logon warning banners. Procedure: An exact match is required to have a valid warning banner. Check for the following login banner. You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. | Edit /etc/issue and the DoD login banner. DoD Login Banners: You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests- -not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. Find the location of the banner file for sshd and examine the content: # grep -i banner /etc/ssh/sshd_config | grep -v '^#' # cat Edit the SSH daemon configuration and add or edit a "Banner" setting referencing a file containing a logon warning banner. |
| V-22490 | CCI-000366 | medium | The system must be configured with a default gateway for IPv6 if the system uses IPv6, unless the system is a router. | If a system has no default gateway defined, the system is at increased risk of man-in-the-middle, monitoring, and Denial of Service attacks. | Check for a default route for IPv6. If the system is a VM host and acts as a router solely for the benefit of its client systems, then this rule is not applicable. # ip -6 route list | grep default If the system uses IPv6, and no results are returned, this is a finding. | Add a default route for IPv6. Edit /etc/sysconfig/network-scripts/ifcfg-eth0 (substitute interface as appropriate). Add an IPV6_DEFAULTGW=<gateway> configuration setting. Restart the interface. # ifdown eth0; ifup eth0 |
| V-22491 | CCI-000366 | medium | The system must not have IP forwarding for IPv6 enabled, unless the system is an IPv6 router. | If the system is configured for IP forwarding and is not a designated router, it could be used to bypass network security by providing a path for communication not filtered by network devices. | Check if the system is configured for IPv6 forwarding. # grep [01] /proc/sys/net/ipv6/conf/*/forwarding|egrep "default|all" If all of the resulting lines do not end with 0, this is a finding. | Disable IPv6 forwarding. Edit /etc/sysctl.conf and add a setting for "net.ipv6.conf.all.forwarding=0" and "net.ipv6.conf.default.forwarding=0". Reload the sysctls. Procedure: # sysctl -p |
| V-22492 | CCI-000225 | medium | The Network File System (NFS) export configuration file must be group-owned by root, bin, sys, or system. | Failure to give group-ownership of the NFS export configuration file to root or a system group provides the designated group-owner and possible unauthorized users with the potential to change system configuration which could weaken the system's security posture. | Check the group ownership of the NFS export configuration file. Procedure: # ls -lL /etc/exports If the file is not group-owned by root, bin, sys, or system, this is a finding. | Change the group ownership of the NFS export configuration file. Procedure: # chgrp root /etc/exports |
| V-22493 | CCI-000225 | low | The Network File System (NFS) exports configuration file must not have an extended ACL. | File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the NFS export configuration file could allow unauthorized modification of the file, which could result in Denial of Service to authorized NFS exports and the creation of additional unauthorized exports. | Check the permissions of the NFS export configuration file. # ls -lL /etc/exports If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/exports |
| V-22496 | CCI-000225 | medium | All Network File System (NFS) exported system files and system directories must be group-owned by root, bin, sys, or system. | Failure to give group-ownership of sensitive files or directories to root provides the members of the owning group with the potential to access sensitive information or change system configuration which could weaken the system's security posture. | List the exports. # cat /etc/exports For each file system displayed, check the ownership. # ls -ldL <exported file system path> If the directory is not group-owned by root, bin, sys, or system, this is a finding. | Change the group owner of the export directory. # chgrp root <export> |
| V-22497 | CCI-000225 | medium | The /etc/smb.conf file must not have an extended ACL. | Excessive permissions could endanger the security of the Samba configuration file and, ultimately, the system and network. | Check the permissions of the Samba configuration file. # ls -lL /etc/samba/smb.conf If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/samba/smb.conf |
| V-22498 | CCI-000225 | medium | The /etc/smbpasswd file must not have an extended ACL. | If the permissions of the "smbpasswd" file are too permissive, it may be maliciously accessed or modified, potentially resulting in the compromise of Samba accounts. | Check the permissions of the Samba password files. Procedure: # ls -lL /etc/samba/passdb.tdb /etc/samba/secrets.tdb If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/samba/passdb.tdb /etc/samba/secrets.tdb |
| V-22499 | CCI-000366 | medium | Samba must be configured to use an authentication mechanism other than "share." | Samba share authentication does not provide for individual user identification and must not be used. | Check the security mode of the Samba configuration. # grep -i security /etc/samba/smb.conf If the security mode is "share", this is a finding. | Edit the "/etc/samba/smb.conf" file and change the "security" setting to "user" or another valid setting other than "share". |
| V-22500 | CCI-000366 | medium | Samba must be configured to use encrypted passwords. | Samba must be configured to protect authenticators. If Samba passwords are not encrypted for storage, plain-text user passwords may be read by those with access to the Samba password file. | Check the encryption setting of Samba. # grep -i 'encrypt passwords' /etc/samba/smb.conf If the setting is not present, or not set to 'yes', this is a finding. | Edit the "/etc/samba/smb.conf" file and change the "encrypt passwords" setting to "yes". |
| V-22501 | CCI-000366 | medium | Samba must be configured to not allow guest access to shares. | Guest access to shares permits anonymous access and is not permitted. | Check the access to shares for Samba. # grep -i 'guest ok' /etc/samba/smb.conf If the setting exists and is set to 'yes', this is a finding. | Edit the "/etc/samba/smb.conf" file and change the "guest ok" setting to "no". |
| V-22502 | CCI-000225 | medium | The /etc/news/hosts.nntp file must not have an extended ACL. | File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the "hosts.nntp" file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users. | Check the permissions of the file. # ls -lL /etc/news/hosts.nntp If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/news/hosts.nntp |
| V-22503 | CCI-000225 | medium | The /etc/news/hosts.nntp.nolimit file must not have an extended ACL. | File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the hosts.nntp.nolimit file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users. | Check the permissions for "/etc/news/hosts.nntp.nolimit". # ls -lL /etc/news/hosts.nntp.nolimit If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/news/hosts.nntp.nolimit |
| V-22504 | CCI-000225 | medium | The /etc/news/nnrp.access file must not have an extended ACL. | File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. Excessive permissions on the nnrp.access file may allow unauthorized modification which could lead to Denial of Service to authorized users or provide access to unauthorized users. | Check the permissions of the file. # ls -lL /etc/news/nnrp.access If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/news/nnrp.access |
| V-22505 | CCI-000225 | medium | The /etc/news/passwd.nntp file must not have an extended ACL. | Extended ACLs may provide excessive permissions on the /etc/news/passwd.nntp file, which may permit unauthorized access or modification to the NNTP configuration. | Check the permissions of the file. # ls -lL /etc/news/passwd.nntp If the mode includes a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/news/passwd.nntp |
| V-22506 | CCI-000366 | medium | The system package management tool must be used to verify system software periodically. | Verification using the system package management tool can be used to determine that system software has not been tampered with. This requirement is not applicable to systems not using package management tools. | Check the root crontab (crontab -l) and the global crontabs in "/etc/crontab", "/etc/cron.*" for the presence of an rpm verification command such as: rpm -qVa | awk '$2!="c" {print $0}' If no such cron job is found, this is a finding. If the result of the cron job indicates packages which do not pass verification exist, this is a finding. | Add a cron job to run an rpm verification command such as: rpm -qVa | awk '$2!="c" {print $0}' For packages which failed verification: If the package is not necessary for operations, remove it from the system. If the package is necessary for operations, re-install the package. |
| V-22507 | CCI-001297 | low | The file integrity tool must be configured to verify ACLs. | ACLs can provide permissions beyond those permitted through the file mode and must be verified by file integrity tools. | If using an Advanced Intrusion Detection Environment (AIDE), verify that the configuration contains the "ACL" option for all monitored files and directories. Procedure: Check for the default location /etc/aide/aide.conf or: # find / -name aide.conf # egrep "[+]?acl" <aide.conf file> If the option is not present. This is a finding. If using a different file integrity tool, check the configuration per tool documentation. | If using AIDE, edit the configuration and add the "ACL" option for all monitored files and directories. If using a different file integrity tool, configure ACL checking per the tool's documentation. |
| V-22508 | CCI-001297 | low | The file integrity tool must be configured to verify extended attributes. | Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications. | If using an Advanced Intrusion Detection Environment (AIDE), verify the configuration contains the "xattrs" option for all monitored files and directories. Procedure: Check for the default location /etc/aide/aide.conf or: # find / -name aide.conf # egrep "[+]?xattrs" <aide.conf file> If the option is not present. This is a finding. If using a different file integrity tool, check the configuration per tool documentation. | If using AIDE, edit the configuration and add the "xattrs" option for all monitored files and directories. If using a different file integrity tool, configure extended attributes checking per the tool's documentation. |
| V-22509 | CCI-001297 | low | The file integrity tool must use FIPS 140-2 approved cryptographic hashes for validating file contents. | File integrity tools often use cryptographic hashes for verifying that file contents have not been altered. These hashes must be FIPS 140-2 approved. | If using an Advanced Intrusion Detection Environment (AIDE), verify the configuration contains the "sha256" or "sha512" options for all monitored files and directories. Procedure: Check for the default location /etc/aide/aide.conf or: # find / -name aide.conf # egrep "[+]?(sha256|sha512)" <aide.conf file> If the option is not present. This is a finding. If one of these options is not present. This is a finding. If using a different file integrity tool, check the configuration per tool documentation. | If using AIDE, edit the configuration and add the "sha512" option for all monitored files and directories. If using a different file integrity tool, configure FIPS 140-2 approved cryptographic hashes per the tool's documentation. |
| V-22511 | CCI-000382 | medium | The Stream Control Transmission Protocol (SCTP) must be disabled unless required. | The Stream Control Transmission Protocol (SCTP) is an Internet Engineering Task Force (IETF)-standardized transport layer protocol. This protocol is not yet widely used. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol. | Verify the SCTP protocol handler is prevented from dynamic loading. # grep 'install sctp /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no result is returned, this is a finding. | Prevent the SCTP protocol handler for dynamic loading. # echo "install sctp /bin/true" >> /etc/modprobe.conf |
| V-22514 | CCI-000382 | medium | The Datagram Congestion Control Protocol (DCCP) must be disabled unless required. | The DCCP is a proposed transport layer protocol. This protocol is not yet widely used. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol. | Verify the DCCP protocol handler is prevented from dynamic loading. # grep 'install dccp /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no result is returned, this is a finding. # grep 'install dccp_ipv4 /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no result is returned, this is a finding. # grep 'install dccp_ipv6 /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no result is returned, this is a finding. | Prevent the DCCP protocol handler for dynamic loading. # echo "install dccp /bin/true" >> /etc/modprobe.conf # echo "install dccp_ipv4 /bin/true" >> /etc/modprobe.conf # echo "install dccp_ipv6 /bin/true" >> /etc/modprobe.conf |
| V-22524 | CCI-000382 | medium | The AppleTalk protocol must be disabled or not installed. | The AppleTalk suite of protocols is no longer in common use. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol. | Verify the AppleTalk protocol handler is prevented from dynamic loading. # grep 'install appletalk' /etc/modprobe.conf /etc/modprobe.d/* If anything is returned check that appletalk is disabled by having the executable set to '/bin/true'. If an uncommented line containing "appletalk" is found which has not been disabled, this is a finding. | Prevent the AppleTalk protocol handler for dynamic loading. # echo "install appletalk /bin/true" >> /etc/modprobe.conf |
| V-22530 | CCI-000382 | medium | The Reliable Datagram Sockets (RDS) protocol must be disabled or not installed unless required. | The RDS protocol is a relatively new protocol developed by Oracle for communication between the nodes of a cluster. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol. | Ask the SA if RDS is required by application software running on the system. If so, this is not applicable. Verify the RDS protocol handler is prevented from dynamic loading. # grep 'install rds /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no result is returned, this is a finding. | Prevent the RDS protocol handler for dynamic loading. # echo "install rds /bin/true" >> /etc/modprobe.conf |
| V-22533 | CCI-000382 | medium | The Transparent Inter-Process Communication (TIPC) protocol must be disabled or uninstalled. | The TIPC protocol is a relatively new cluster communications protocol developed by Ericsson. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol. | Verify the TIPC protocol handler is prevented from dynamic loading. # grep 'install tipc /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no result is returned, this is a finding. | Prevent the TIPC protocol handler for dynamic loading. # echo "install tipc /bin/true" >> /etc/modprobe.conf |
| V-22539 | CCI-001551 | medium | The Bluetooth protocol handler must be disabled or not installed. | Bluetooth is a Personal Area Network (PAN) technology. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the kernel to dynamically load a protocol handler by opening a socket using the protocol. | Verify the Bluetooth protocol handler is prevented from dynamic loading. # grep 'install bluetooth /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no result is returned, this is a finding. | Prevent the Bluetooth protocol handler for dynamic loading. # echo "install bluetooth /bin/true" >> /etc/modprobe.conf |
| V-22541 | CCI-001551 | medium | The IPv6 protocol handler must not be bound to the network stack unless needed. | IPv6 is the next version of the Internet protocol. Binding this protocol to the network stack increases the attack surface of the host. | If the IPv6 protocol handler is bound to the network stack, and the system does not need IPv6, this is a finding. # grep NETWORKING_IPV6 /etc/sysconfig/network If the line is set to "yes", this is a finding. | Remove the capability to use IPv6 protocol handler. Procedure: Edit /etc/sysconfig/network and change NETWORKING_IPV6=yes to NETWORKING_IPV6=no Edit /etc/modprobe.conf and add these lines (if they are not in it): alias net-pf-10 off alias ipv6 off Stop the ipv6tables service by typing: service ip6tables stop Disable the ipv6tables service by typing: chkconfig ip6tables off Remove the ipv6 kernel module # rmmod ipv6 Reboot |
| V-22542 | CCI-001551 | medium | The IPv6 protocol handler must be prevented from dynamic loading unless needed. | IPv6 is the next generation of the Internet protocol. Binding this protocol to the network stack increases the attack surface of the host. Unprivileged local processes may be able to cause the system to dynamically load a protocol handler by opening a socket using the protocol. | If this system uses IPv6, this is not applicable. Verify the IPv6 protocol handler is prevented from dynamic loading. # grep 'install ipv6 /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no result is returned, this is a finding. | Prevent the IPv6 protocol handler for dynamic loading. # echo "install ipv6 /bin/true" >> /etc/modprobe.conf |
| V-22545 | CCI-001551 | medium | The system must not have 6to4 enabled. | 6to4 is an IPv6 transition mechanism involving tunneling IPv6 packets encapsulated in IPv4 packets on an ad-hoc basis. This is not a preferred transition strategy and increases the attack surface of the system. | Check the system for any active 6to4 tunnels without specific remote addresses. # ip tun list | grep "remote any" | grep "ipv6/ip" If any results are returned the "tunnel" is the first field. If any results are returned, this is a finding. | Disable the active 6to4 tunnel. # ip link set <tunnel> down Add this command to a startup script, or remove the configuration creating the tunnel. |
| V-22546 | CCI-001551 | medium | The system must not have Teredo enabled. | Teredo is an IPv6 transition mechanism involving tunneling IPv6 packets encapsulated in IPv4 packets. Unauthorized tunneling may circumvent network security. | Verify the Miredo service is not running. # ps ax | grep miredo | grep -v grep If the miredo process is running, this is a finding. | Edit startup scripts to prevent the service from running on startup. |
| V-22547 | CCI-001551 | medium | The system must not have IP tunnels configured. | IP tunneling mechanisms can be used to bypass network filtering. | Check for any IP tunnels. # ip tun list # ip -6 tun list If any tunnels are listed, this is a finding. | Remove the tunnels. # ip tun del <tunnel> Edit system startup scripts to prevent tunnel creation on startup. |
| V-22548 | CCI-000366 | medium | The DHCP client must be disabled if not needed. | DHCP allows for the unauthenticated configuration of network parameters on the system by exchanging information with a DHCP server. | Verify no interface is configured to use DHCP. # grep -i bootproto=dhcp /etc/sysconfig/network-scripts/ifcfg-* If any configuration is found, this is a finding. | Edit the "/etc/sysconfig/network-scripts/ifcfg-*" file(s) and change the "bootproto" setting to "static". |
| V-22549 | CCI-000366 | medium | The DHCP client must not send dynamic DNS updates. | Dynamic DNS updates transmit unencrypted information about a system including its name and address and should not be used unless needed. | Verify the DHCP client is configured to not send dynamic DNS updates. Procedure: # grep do-forward-updates /etc/dhclient.conf If the file is not present, does not contain this configuration, or has the setting set to "true", this is a finding. | Edit or add the "/etc/dhclient.conf" file and add or edit the "do-forward-updates" setting to false. Procedure: # echo "do-forward-updates false;" >> /etc/dhclient.conf |
| V-22550 | CCI-001551 | medium | The system must ignore IPv6 ICMP redirect messages. | ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. | Verify the system is configured to ignore IPv6 ICMP redirect messages. # cat /proc/sys/net/ipv6/conf/all/accept_redirects If the returned value is not "0", this is a finding. | Configure the system to ignore IPv6 ICMP redirect messages. Edit "/etc/sysctl.conf" and add a settings for "net.ipv6.conf.default.accept_redirects=0" and "net.ipv6.conf.all.accept_redirects=0". Restart the system for the setting to take effect. |
| V-22553 | CCI-001551 | medium | The system must not forward IPv6 source-routed packets. | Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router. | Determine if the system is configured to forward IPv6 source-routed packets. Procedure: # egrep "net.ipv6.conf.*forwarding" /etc/sysctl.conf If there are no entries found or the value of the entries is not = "0", this is a finding. | Configure the system to not forward IPv6 source-routed packets. Procedure: Edit the /etc/sysctl.conf file to include: net.ipv6.conf.all.forwarding = 0 net.ipv6.conf.default.forwarding = 0 Reload the kernel parameters: # sysctl -p |
| V-22555 | CCI-001453 | medium | If the system is using LDAP for authentication or account information, the system must use a TLS connection using FIPS 140-2 approved cryptographic algorithms. | LDAP can be used to provide user authentication and account information, which are vital to system security. Communication between an LDAP server and a host using LDAP requires protection. | Check if the system is using NSS LDAP. # grep -v '^#' /etc/nsswitch.conf | grep ldap If no lines are returned, this vulnerability is not applicable. Check if NSS LDAP is using TLS. # grep '^ssl start_tls' /etc/ldap.conf If no lines are returned, this is a finding. Check if NSS LDAP TLS is using only FIPS 140-2 approved cryptographic algorithms. # grep '^tls_ciphers' /etc/ldap.conf If the line is not present, or contains ciphers not approved by FIPS 140-2, this is a finding. FIPS approved ciphers include 3DES and AES. FIPS approved hashes include the SHA hash family. | Edit "/etc/ldap.conf" and add a "ssl start_tls" and "tls_ciphers" options with only FIPS 140-2 approved ciphers. |
| V-22556 | CCI-000185 | medium | If the system is using LDAP for authentication or account information, certificates used to authenticate to the LDAP server must be provided from DoD PKI or a DoD-approved external PKI. | LDAP can be used to provide user authentication and account information, which are vital to system security. Communication between an LDAP server and a host using LDAP requires authentication. | Verify the source of the LDAP certificates Check if the system is using NSS LDAP. # grep -v '^#' /etc/nsswitch.conf | grep ldap If no lines are returned, this vulnerability is not applicable. Verify with the SA that the system is connected to the GIG. If the system part of a stand alone network which is not connected to the GIG this vulnerability is not applicable. Verify a certificate is used for client authentication to the server. # grep -i '^tls_cert' /etc/ldap.conf If no line is found, this is a finding. List the certificate issuer. # openssl x509 -text -in <cert> If the certificate is not issued by DoD PKI or a DoD-approved external PKI, this is a finding. | Edit "/etc/ldap.conf" and add or edit the 'tls_cert' setting to reference a file containing a client certificate issued by DoD PKI or a DoD-approved external PKI. |
| V-22557 | CCI-000185 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS connection must require the server provide a certificate with a valid trust path to a trusted CA. | The NSS LDAP service provides user mappings which are a vital component of system security. Communication between an LDAP server and a host using LDAP for NSS require authentication. | Check if the system is using NSS LDAP. # grep -v '^#' /etc/nsswitch.conf | grep ldap If no lines are returned, this vulnerability is not applicable. Verify a server certificate is required and verified by the NSS LDAP configuration. # grep -i '^tls_checkpeer' /etc/ldap.conf If no line is returned, or the value is not "yes", this is a finding. | Edit "/etc/ldap.conf" and add or set the "tls_checkpeer" setting to "yes". |
| V-22558 | CCI-000185 | medium | If the system is using LDAP for authentication or account information, the system must verify the LDAP server's certificate has not been revoked. | LDAP can be used to provide user authentication and account information, which are vital to system security. Communication between an LDAP server and a host using LDAP requires authentication. | Check if the system is using NSS LDAP. # grep -v '^#' /etc/nsswitch.conf | grep ldap If no lines are returned, this vulnerability is not applicable. Verify the NSS LDAP client is configured to check certificates against a certificate revocation list. # grep -i '^tls_crlcheck' /etc/ldap.conf If the setting does not exist, or the value is not "all", this is a finding. | Edit "/etc/ldap.conf" and add or set the "tls_crlcheck" setting to "all". |
| V-22559 | CCI-000225 | medium | If the system is using LDAP for authentication or account information the /etc/ldap.conf (or equivalent) file must have mode 0644 or less permissive. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Check the permissions of the file. # ls -lL /etc/ldap.conf If the mode of the file is more permissive than 0644, this is a finding. | Change the permissions of the file. # chmod 0644 /etc/ldap.conf |
| V-22560 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the /etc/ldap.conf (or equivalent) file must be owned by root. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Check the ownership of the file. # ls -lL /etc/ldap.conf If the file is not owned by root, this is a finding. | Change the owner of the file. # chown root /etc/ldap.conf |
| V-22561 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the /etc/ldap.conf (or equivalent) file must be group-owned by root, bin, sys, or system. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Check the group ownership of the file. Procedure: # ls -lL /etc/ldap.conf If the file is not group-owned by root, bin, sys, or system, this is a finding. | Change the group owner of the file to root, bin, sys, or system. Procedure: # chgrp root /etc/ldap.conf |
| V-22562 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the /etc/ldap.conf (or equivalent) file must not have an extended ACL. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Check the permissions of the file. # ls -lL /etc/ldap.conf If the mode includes a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the "/etc/ldap.conf" file. # setfacl --remove-all /etc/ldap.conf |
| V-22563 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the TLS certificate authority file and/or directory (as appropriate) must be owned by root. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine if LDAP is used for account information on the system. # grep -i ldap /etc/nsswitch.conf If no un-commented reference to "ldap" is identified, LDAP is not used for account information on the system and this is not applicable. Determine the certificate authority file and/or directory. # grep -i '^tls_cacert' /etc/ldap.conf For each file or directory returned, check the ownership. # ls -lLd <certpath> If the owner of any file or directory is not root, this is a finding. | Change the ownership of the file or directory. # chown root <certpath> |
| V-22564 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the TLS certificate authority file and/or directory (as appropriate) must be group-owned by root, bin, sys, or system. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification | Determine the certificate authority file and/or directory. # grep -i '^tls_cacert' /etc/ldap.conf For each file or directory returned, check the group ownership. # ls -lLd <certpath> If the group-owner of any file or directory is not root, bin, sys, or system, this is a finding. | Change the group ownership of the file or directory. # chgrp root <certpath> |
| V-22565 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the TLS certificate authority file and/or directory (as appropriate) must have mode 0644 (0755 for directories) or less permissive. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine the certificate authority file and/or directory. Procedure: # grep -i '^tls_cacert' /etc/ldap.conf For each file or directory returned, check the permissions. Procedure: # ls -lLd <certpath> If the mode of the file is more permissive than 0644 (or 0755 for directories), this is a finding. | Change the mode of the file or directory. File Procedure: # chmod 0644 <certpath> Directory Procedure: # chmod 0755 <certpath> |
| V-22566 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS certificate authority file and/or directory (as appropriate) must not have an extended ACL. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine the certificate authority file and/or directory. # grep -i '^tls_cacert' /etc/ldap.conf For each file or directory returned, check the permissions. # ls -lLd <certpath> If the mode of the file or directory contains a '+', an extended ACL is present. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the certificate file. Procedure: For each certificate file found remove all extended permissions # setfacl --remove-all <certpath> |
| V-22567 | CCI-000225 | medium | For systems using NSS LDAP, the TLS certificate file must be owned by root. | The NSS LDAP service provides user mappings which are a vital component of system security. Its configuration must be protected from unauthorized modification. | Determine the certificate file. # grep -i '^tls_cert' /etc/ldap.conf Check the ownership. # ls -lL <certpath> If the owner of the file is not root, this is a finding. | Change the ownership of the file. # chown root <certpath> |
| V-22568 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS certificate file must be group-owned by root, bin, sys, or system. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine the certificate file. Procedure: # grep -i '^tls_cert' /etc/ldap.conf Check the group ownership. Procedure: # ls -lL <certpath> If the group owner of the file is not root, bin, sys, or system, this is a finding. | Change the group ownership of the file. Procedure: # chgrp root <certpath> |
| V-22569 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS certificate file must have mode 0644 or less permissive. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine the certificate file. # grep -i '^tls_cacert' /etc/ldap.conf Check the permissions. # ls -lL <certpath> If the mode of the file is more permissive than 0644, this is a finding. | Change the mode of the file. # chmod 0644 <certpath> |
| V-22570 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS certificate file must not have an extended ACL. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine the certificate file. # grep -i '^tls_cert' /etc/ldap.conf Check the permissions. # ls -lL <certpath> If the mode of the file contains a '+', an extended ACL is present. This is a finding. | Remove the extended ACL from the certificate file. Procedure: For each certificate file found remove all extended permissions. # setfacl --remove-all <certpath> |
| V-22571 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS key file must be owned by root. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine the key file. # grep -i '^tls_key' /etc/ldap.conf Check the ownership. # ls -lL <keypath> If the owner of the file is not root, this is a finding. | Change the ownership of the file. # chown root <keypath> |
| V-22572 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS key file must be group-owned by root, bin, or sys. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine the key file. # grep -i '^tls_key' /etc/ldap.conf Check the group ownership. # ls -lL <keypath> If the file is not group owned by root, bin, or sys, this is a finding. | Change the group ownership of the file. # chgrp root <keypath> |
| V-22573 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS key file must have mode 0600 or less permissive. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. Note: Depending on the particular implementation, group and other read permission may be necessary for unprivileged users to successfully resolve account information using LDAP. This will still be a finding, as these permissions provide users with access to system authenticators. | Determine the key file. # grep -i '^tls_key' /etc/ldap.conf Check the permissions. # ls -lL <keypath> If the mode of the file is more permissive than 0600, this is a finding. | Change the mode of the file. # chmod 0600 <keypath> |
| V-22574 | CCI-000225 | medium | If the system is using LDAP for authentication or account information, the LDAP TLS key file must not have an extended ACL. | LDAP can be used to provide user authentication and account information, which are vital to system security. The LDAP client configuration must be protected from unauthorized modification. | Determine the key file. # grep -i '^tls_key' /etc/ldap.conf Check the permissions. # ls -lL <keypath> If the permissions of the file contains a '+', an extended ACL is present. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the key file. Procedure: For each key file found remove all extended permissions. # setfacl --remove-all <keypath> |
| V-22575 | CCI-001199 | medium | A root kit check tool must be run on the system at least weekly. | Root kits are software packages designed to conceal the compromise of a system from the SA. Root kit checking tools examine a system for evidence that a root kit is installed. Dedicated root kit detection software or root kit detection capabilities included in anti-virus packages may be used to satisfy this requirement. | Ask the SA if a root kit check tool is run on the system weekly. If this is not performed, this is a finding. | Create an automated job or establish a site-defined procedure to check the system weekly with a root kit check tool. |
| V-22576 | CCI-000366 | low | The system must use available memory address randomization techniques. | Successful exploitation of buffer overflow vulnerabilities relies in some measure to having a predictable address structure of the executing program. Address randomization techniques reduce the probability of a successful exploit. | Verify exec-shield is enabled if present. # cat /proc/sys/kernel/exec-shield If the file is present and contains a value of "0", this is a finding. | Edit the kernel boot parameters, or "/etc/sysctl.conf", and set exec-shield to "1". Reboot the system. |
| V-22577 | CCI-000366 | low | Automated file system mounting tools must not be enabled unless needed. | Automated file system mounting tools may provide unprivileged users with the ability to access local media and network shares. If this access is not necessary for the system’s operation, it must be disabled to reduce the risk of unauthorized access to these resources. | If the autofs service is needed, this vulnerability is not applicable. Check if the autofs service is running. # service autofs status If the service is running, this is a finding. | Stop and disable the autofs service. # service autofs stop # chkconfig autofs off |
| V-22578 | CCI-000366 | low | The system must have USB disabled unless needed. | USB is a common computer peripheral interface. USB devices may include storage devices with the potential to install malicious software on a system or exfiltrate data. | If the system needs USB, this vulnerability is not applicable. Check if the directory "/proc/bus/usb" exists. If so, this is a finding. | Edit the grub bootloader file "/boot/grub/grub.conf" or "/boot/grub/menu.lst" by appending the "nousb" parameter to the kernel boot line. |
| V-22579 | CCI-000366 | low | The system must have USB Mass Storage disabled unless needed. | USB is a common computer peripheral interface. USB devices may include storage devices with the potential to install malicious software on a system or exfiltrate data | If the system needs USB storage, this vulnerability is not applicable. Check if usb-storage is prevented from loading. # grep 'install usb-storage /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no results are returned, this is a finding. | Prevent the usb-storage module from loading. # echo 'install usb-storage /bin/true' >> /etc/modprobe.conf |
| V-22580 | CCI-000366 | low | The system must have IEEE 1394 (Firewire) disabled unless needed. | Firewire is a common computer peripheral interface. Firewire devices may include storage devices with the potential to install malicious software on a system or exfiltrate data. | If the system needs IEEE 1394 (Firewire), this is not applicable. Check if the firewire module is not disabled. # grep 'install ieee1394 /bin/true' /etc/modprobe.conf /etc/modprobe.d/* If no results are returned, this is a finding. | Prevent the system from loading the firewire module. # echo 'install ieee1394 /bin/true' >> /etc/modprobe.conf |
| V-22582 | CCI-001118 | medium | The system must employ a local firewall. | A local firewall protects the system from exposing unnecessary or undocumented network services to the local enclave. If a system within the enclave is compromised, firewall protection on an individual system continues to protect it from attack. | Determine if the system is using a local firewall. # chkconfig --list iptables If the service is not "on" in the standard runlevel (ordinarily 3 or 5), this is a finding. | Enable the system's local firewall. # chkconfig iptables on # service iptables start |
| V-22583 | CCI-001109 | medium | The system's local firewall must implement a deny-all, allow-by-exception policy. | A local firewall protects the system from exposing unnecessary or undocumented network services to the local enclave. If a system within the enclave is compromised, firewall protection on an individual system continues to protect it from attack. | Check the firewall rules for a default deny rule. # iptables --list Example of a rule meeting this criteria: REJECT all -- anywhere anywhere reject-with icmp-host-prohibited A rule using DROP is also acceptable. The default rule should be the last rule of a table and match all traffic. If there is no default deny rule, this is a finding. | Edit "/etc/sysconfig/iptables" and add a default deny rule. An example of a default deny rule: -A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited Restart the iptable service. # service iptables restart |
| V-22584 | CCI-000032 | low | The system must use a Linux Security Module configured to limit the privileges of system services. | Linux Security Modules such as SELinux and AppArmor can be used to provide protection from software exploits by explicitly defining the privileges permitted to each software package. | Check if SELinux is enabled with at least a "targeted" policy. # grep ^SELINUX /etc/sysconfig/selinux If the SELINUX option is not set to "enforcing", this is a finding. If the SELINUXTYPE option is not set to "targeted" or "strict", this is a finding. If the use of the system is incompatible with the confines of SELinux this rule may be waived. | Enable one of the SELinux prolicies. Edit /etc/sysconfig/selinux and set the value of the SELINUX option to "enforcing" and SELINUXTYPE to "targeted" or "strict". Restart the system. |
| V-22585 | CCI-000225 | medium | The system's boot loader configuration file(s) must not have extended ACLs. | File system extended ACLs provide access to files beyond what is allowed by the mode numbers of the files. If extended ACLs are present on the system's boot loader configuration file(s), these files may be vulnerable to unauthorized access or modification, which could compromise the system's boot process. | Check the permissions of the file. # ls -lL /boot/grub/grub.conf If the permissions of the file or directory contains a '+', an extended ACL is present. This is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/grub.conf |
| V-22586 | CCI-000225 | medium | The system's boot loader configuration files must be owned by root. | The system's boot loader configuration files are critical to the integrity of the system and must be protected. Unauthorized modification of these files resulting from improper ownership could compromise the system's boot loader configuration. | Check the ownership of the file. # ls -lLd /boot/grub/grub.conf If the owner of the file is not root, this is a finding. | Change the ownership of the file. # chown root /boot/grub/grub.conf |
| V-22587 | CCI-000225 | medium | The system's boot loader configuration file(s) must be group-owned by root, bin, sys, or system. | The system's boot loader configuration files are critical to the integrity of the system and must be protected. Unauthorized modifications resulting from improper group ownership may compromise the boot loader configuration. | Check the group ownership of the file. # ls -lLd /boot/grub/grub.conf If the group-owner of the file is not root, bin, sys, or system this is a finding. | Change the group ownership of the file. # chgrp root /boot/grub/grub.conf |
| V-22588 | CCI-000351 | low | The system package management tool must cryptographically verify the authenticity of software packages during installation. | To prevent the installation of software from unauthorized sources, the system package management tool must use cryptographic algorithms to verify the packages are authentic. | Verify RPM signature validation is not disabled. # grep nosignature /etc/rpmrc /usr/lib/rpm/rpmrc /usr/lib/rpm/redhat/rpmrc ~root/.rpmrc If any configuration is found, this is a finding. Verify YUM signature validation is not disabled. # grep gpgcheck /etc/yum.conf /etc/yum.repos.d/* If any "gpgcheck" setting is returned that is not equal to "1", this is a finding. | Edit the RPM configuration file containing the "nosignature" option and remove the option. Edit the YUM configuration containing "gpgcheck=0" and set the value to "1". |
| V-22589 | CCI-001233 | low | The system package management tool must not automatically obtain updates. | System package management tools can obtain a list of updates and patches from a package repository and make this information available to the SA for review and action. Using a package repository outside of the organization's control presents a risk of malicious packages being introduced. | Verify the YUM service is enabled. # service yum-updatesd status If the service is enabled, this is a finding. | Disable the yum service. # chkconfig yum-updatesd off ; service yum-updatesd stop |
| V-22595 | CCI-000225 | medium | The access.conf file must not have an extended ACL. | If the access permissions are more permissive than 0640, system security could be compromised. | Check the permissions of the file. # ls -lL /etc/security/access.conf If the permissions of the file or directory contain a '+', an extended ACL is present. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/security/access.conf |
| V-22596 | CCI-000225 | medium | The /etc/sysctl.conf file must not have an extended ACL. | The sysctl.conf file specifies the values for kernel parameters to be set on boot. These settings can affect the system's security. | Check the permissions of the file. # ls -lL /etc/sysctl.conf If the permissions of the file or directory contain a '+', an extended ACL is present. If the file has an extended ACL and it has not been documented with the IAO, this is a finding. | Remove the extended ACL from the file. # setfacl --remove-all /etc/sysctl.conf |
| V-22598 | CCI-000032 | low | Auditing must be enabled at boot by setting a kernel parameter. | If auditing is enabled late in the boot process, the actions of startup scripts may not be audited. Some audit systems also maintain state information only available if auditing is enabled before a given process is created. | Check for the audit=1 kernel parameter. # grep 'audit=1' /proc/cmdline If no results are returned, this is a finding. | Edit the grub bootloader file /boot/grub/grub.conf or /boot/grub/menu.lst by appending the "audit=1" parameter to the kernel boot line. Reboot the system for the change to take effect. |
| V-22665 | CCI-000366 | medium | The system must not be running any routing protocol daemons, unless the system is a router. | Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. | Check for any running routing protocol daemons. If the system is a VM host and acts as a router solely for the benefits of its client systems, then this rule is not applicable. # chkconfig --list |grep :on|egrep '(ospf|route|bgp|zebra|quagga)' If any routing protocal daemons are listed, this is a finding. | Disable any routing protocol daemons. |
| V-22702 | CCI-000162 | medium | System audit logs must be group-owned by root, bin, sys, or system. | Sensitive system and user information could provide a malicious user with enough information to penetrate further into the system. | Check the group ownership of the audit logs. Procedure: # grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//|xargs stat -c %G:%n If any audit log file is not group-owned by root, bin, sys, or system, this is a finding. | Change the group ownership of the audit log file(s). Procedure: # chgrp root <audit log file> |
| V-23732 | CCI-000048 | medium | The FTPS/FTP service on the system must be configured with the Department of Defense (DoD) login banner. | Failure to display the logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources. Note: SFTP and FTPS are encrypted alternatives to FTP to be used in place of FTP. SFTP is implemented by the SSH service and uses its banner configuration. | FTP to the system. # ftp localhost Check for either of the following login banners based on the character limitations imposed by the system. An exact match is required. If one of these banners is not displayed, this is a finding. If the system does not run the FTP service, this is not applicable. DoD Login Banners: You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. OR I've read & consent to terms in IS user agreem't. | Provide the proper text for the DoD banner to be presented by the FTP server to the user. For vsftp: Examine the /etc/vsftp.conf file for the "banner_file" entry. (i.e. banner_file = /etc/banner/vsftp) For gssftp: Examine the /etc/xinetd.d/gssftp file for the "banner" entry. (i.e. banner = /etc/banner/gssftp) For both: Add the banner entry if one is not found. Modify or create the referenced banner file to contain one of the following DoD login banners (based on the character limitations imposed by the system). DoD Login Banners: You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. OR I've read & consent to terms in IS user agreem't. |
| V-23736 | CCI-001208 | low | The system must use a separate file system for /var. | The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing. | Determine if the /var path is a separate filesystem. # grep /var /etc/fstab If no result is returned, /var is not on a separate filesystem this is a finding. | Migrate the /var path onto a separate file system. |
| V-23738 | CCI-001208 | low | The system must use a separate file system for the system audit data path. | The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing. | Determine if the /var/log/audit path is a separate filesystem. # grep /var/log/audit /etc/fstab If no result is returned, /var/log/audit is not on a separate filesystem this is a finding. | Migrate the /var/log/audit path onto a separate filesystem. |
| V-23739 | CCI-001208 | low | The system must use a separate file system for /tmp (or equivalent). | The use of separate file systems for different paths can protect the system from failures resulting from a file system becoming full or failing. | Determine if the /tmp path is a separate filesystem. # egrep "[\t ]/tmp[\t ]" /etc/fstab If no result is returned, /tmp is not on a separate filesystem this is a finding. | Migrate the /tmp path onto a separate file system. |
| V-23741 | CCI-000366 | medium | TCP backlog queue sizes must be set appropriately. | To provide some mitigation to TCP Denial of Service attacks, the TCP backlog queue sizes must be set to at least 1280 or in accordance with product-specific guidelines. | # cat /proc/sys/net/ipv4/tcp_max_syn_backlog If the result is not 1280 or greater, this is a finding. | Edit /etc/sysctl.conf and add a setting for "net.ipv4.tcp_max_syn_backlog=1280". Procedure: # sysctl -p |
| V-23952 | CCI-001305 | medium | Mail relaying must be restricted. | If unrestricted mail relaying is permitted, unauthorized senders could use this host as a mail relay for the purpose of sending SPAM or other unauthorized activity. | If the system uses sendmail examine the configuration files. Determine if sendmail only binds to loopback addresses by examining the "DaemonPortOptions" configuration options. Procedure: # grep -i "O DaemonPortOptions" /etc/mail/sendmail.cf If there are uncommented DaemonPortOptions lines, and all such lines specify system loopback addresses, this is not a finding. Otherwise, determine if sendmail is configured to allow open relay operation. Procedure: # grep -i promiscuous_relay /etc/mail/sendmail.mc If the promiscuous relay feature is enabled, this is a finding. If the system uses Postfix, locate the main.cf file. Procedure: # find / -name main.cf Determine if Postfix only binds to loopback addresses by examining the "inet_interfaces" line. Procedure: # grep inet_interfaces </path/to/main.cf> If "inet_interfaces" is set to "loopback-only" or contains only loopback addresses such as 127.0.0.1 and [::1], Postfix is not listening on external network interfaces, and this is not a finding. Otherwise, determine if Postfix is configured to restrict clients permitted to relay mail by examining the "smtpd_client_restrictions" line. Procedure: # grep smtpd_client_restrictions </path/to/main.cf> If the "smtpd_client_restrictions" line is missing, or does not contain "reject", this is a finding. If the line contains "permit" before "reject", this is a finding. If the system is using other SMTP software, consult the software's documentation for procedures to verify mail relaying is restricted. | If the system uses sendmail, edit the sendmail.mc file and remove the "promiscuous_relay" configuration. Rebuild the sendmail.cf file from the modified sendmail.mc and restart the service. If the system does not need to receive mail from external hosts, add one or more DaemonPortOptions lines referencing system loopback addresses (such as "O DaemonPortOptions=Addr=127.0.0.1,Port=smtp,Name=MTA") and remove lines containing non-loopback addresses. Restart the service. If the system uses Postfix, edit the main.cf file and add or edit the "smtpd_client_restrictions" line to have contents "permit mynetworks, reject" or a similarly restrictive rule. If the system does not need to receive mail from external hosts, add or edit the "inet_interfaces" line to have contents "loopback-only" or a set of loopback addresses for the system. Restart the service. If the system is using other SMTP software, consult the software's documentation for procedures to restrict mail relaying. |
| V-23953 | CCI-000305 | medium | The 'ldd' command must be disabled unless it protects against the execution of untrusted files. | The 'ldd' command provides a list of dependent libraries needed by a given binary, which is useful for troubleshooting software. Instead of parsing the binary file, some 'ldd' implementations invoke the program with a special environment variable set, which causes the system dynamic linker to display the list of libraries. Specially crafted binaries can specify an alternate dynamic linker which may cause a program to be executed instead of examined. If the program is from an untrusted source, such as in a user home directory, or a file suspected of involvement in a system compromise, unauthorized software may be executed with the rights of the user running 'ldd'. Some 'ldd' implementations include protections that prevent the execution of untrusted files. If such protections exist, this requirement is not applicable. An acceptable method of disabling 'ldd' is changing its mode to 0000. The SA may conduct troubleshooting by temporarily changing the mode to allow execution and running the 'ldd' command as an unprivileged user upon trusted system binaries. | Check the system for the 'ldd' executable. Procedure: # ls -lL /usr/bin/ldd If the returned line is set to "yes", this is a finding. | Remove the execute permissions from the 'ldd' executable. Procedure: # chmod a-x /usr/bin/ldd |
| V-23972 | CCI-000366 | medium | The system must not respond to ICMPv6 echo requests sent to a broadcast address. | Responding to broadcast ICMP echo requests facilitates network mapping and provides a vector for amplification attacks. | Check for an iptables rule that drops inbound IPv6 ICMP ECHO_REQUESTs sent to the all-hosts multicast address. Procedure: # less /etc/sysconfig/ip6tables Check for a rule in, or referenced by, the INPUT chain such as: -A INPUT -p icmpv6 -d ff02::1 --icmpv6-type 128 -j DROP If such a rule does not exist, this is a finding. | Add an iptables rule that drops inbound IPv6 ICMP ECHO_REQUESTs sent to the all-hosts multicast address. Edit /etc/sysconfig/ip6tables and add a rule in, or referenced by, the INPUT chain such as: -A INPUT -p icmpv6 -d ff02::1 --icmpv6-type 128 -j DROP Reload the iptables rules. Procedure: # service ip6tables restart |
| V-24331 | CCI-000048 | medium | The Department of Defense (DoD) login banner must be displayed immediately prior to, or as part of, graphical desktop environment login prompts. | Failure to display the logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices as well as to graphical desktop environments provided to remote systems, including thin clients. | Access the graphical desktop environment(s) provided by the system and attempt to log in. Check for either of the following login banners based on the character limitations imposed by the system. An exact match is required. If one of these banners is not displayed, this is a finding. You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests- -not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. OR I've read & consent to terms in IS user agreem't. | Configure the system to display one of the DoD login banners prior to, or as part of, the graphical desktop environment login process. Procedure: Modify /usr/share/gdm/themes/RHEL/RHEL.xml by adding the following xml after the first two "pixmap" entries. <item type="rect" id="custom-dod-banner"> <pos anchor="nw" x="20%" y="10" width="80%" height="100%"/> <box> <item type="label"> <normal font="Sans Bold 9" color="#ffffff"/> <text> Insert the "approved text" here based on the character limitations imposed by the system. </text> </item> </box> </item> Approved text: DoD Login Banners: You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. OR I've read & consent to terms in IS user agreem't. |
| V-24347 | CCI-000768 | medium | The system, if capable, must be configured to require the use of a CAC, PIV compliant hardware token, or Alternate Logon Token (ALT) for authentication. | In accordance with CTO 07-015 PKI authentication is required. This provides stronger, two-factor authentication than using a username/password. NOTE: The following are exempt from this, however, they must meet all password requirements and must be documented with the IAO: - SIPRNET systems. - Stand-alone systems. - Application Accounts. - Students or unpaid employees (such as, interns) who are not eligible to receive or not in receipt of a CAC, PIV, or ALT. - Warfighters and support personnel located at operational tactical locations conducting wartime operations that are not collocated with RAPIDS workstations to issue CAC; are not eligible for CAC or do not have the capability to use ALT. - Test systems that have an Interim Approval to Test (IATT) and provide protection via separate VPN, firewall, or security measures preventing access to network and system components from outside the protection boundary documented in the IATT. | Consult vendor documentation to determine if the system is capable of CAC authentication. If it is not, this is not applicable. Interview the SA to determine if all accounts not exempted by policy are using CAC authentication. If non-exempt accounts are not using CAC authentication, this is a finding. | Consult vendor documentation to determine the procedures necessary for configuring CAC authentication. Configure all accounts required by policy to use CAC authentication. |
| V-24357 | CCI-000136 | low | The system must be configured to send audit records to a remote audit server. | Audit records contain evidence that can be used in the investigation of compromised systems. To prevent this evidence from compromise, it must be sent to a separate system continuously. Methods for sending audit records include, but are not limited to, system audit tools used to send logs directly to another host or through the system's syslog service to another host. | Verify the system is configured to forward all audit records to a remote server. If the system is not configured to provide this function, this is a finding. Procedure: Ensure the audit option for the kernel is enabled. # grep "audit" /boot/grub/grub.conf If the kernel does not have the "audit=1" option specified, this is a finding. Ensure the kernel auditing is active. # grep "active" /etc/audisp/plugins.d/syslog.conf If the "active" setting is either missing or not set to "yes", this is a finding. Ensure all audit records are forwarded to a remote server. # grep "\*.\*" /etc/syslog.conf |grep "@" (for syslog) or: # grep "\*.\*" /etc/rsyslog.conf | grep "@" (for rsyslog) If neither of these lines exist, it is a finding. | Configure the system to send audit records to a remote server. Procedure: These instructions assume a known remote audit server is available to this system. Modify /etc/syslog.conf to contain a line sending all audit records to a remote audit server. The server is specified by placing an "@" before the DNS name or IP address in the line. *.* @<remote audit server> Edit the "active" line in /etc/audisp/plugins.d/syslog.conf so it shows "active = yes". Restart audit and syslog: # service auditd restart # service syslog restart |
| V-24384 | CCI-000196 | medium | If the system is using LDAP for authentication or account information, the /etc/ldap.conf file (or equivalent) must not contain passwords. | The authentication of automated LDAP connections between systems must not use passwords since more secure methods are available, such as PKI and Kerberos. Additionally, the storage of unencrypted passwords on the system is not permitted. | Check for the "bindpw" option being used in the "/etc/ldap.conf" file. # grep bindpw /etc/ldap.conf If an uncommented "bindpw" option is returned then a cleartext password is in the file, this is a finding. | Edit the "/etc/ldap.conf" file to use anonymous binding by removing the "bindpw" option. |
| V-24386 | CCI-000197 | high | The telnet daemon must not be running. | The telnet daemon provides a typically unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to log on using this service, the privileged user password could be compromised. | The telnet service included in the RHEL distribution is part of krb5-workstation. There are two versions of telnetd server provided. The xinetd.d file ekrb5-telnet allows only connections authenticated through kerberos. The xinetd.d krb5-telnet allows normal telnet connections as well as kerberized connections. Both are set to "disable = yes" by default. Ensure that neither is running. Procedure: Check if telnetd is running: # ps -ef |grep telnetd If the telnet daemon is running, this is a finding. Check if telnetd is enabled on startup: # chkconfig --list|grep telnet If an entry with "on" is found, this is a finding. | Identify the telnet service running and disable it. Procedure: Disable the telnet server. # chkconfig telnet off Verify the telnet daemon is no longer running. # ps -ef |grep telnet |
| V-24624 | CCI-000213 | medium | The system boot loader must protect passwords using an MD5 or stronger cryptographic hash. | If system boot loader passwords are compromised, users with console access to the system may be able to alter the system boot configuration or boot the system into single user or maintenance mode, which could result in Denial of Service or unauthorized privileged access to the system. | Check GRUB for password configuration. Procedure: Check the /boot/grub/grub.conf or /boot/grub/menu.lst files. # grep "password" /boot/grub/grub.conf /boot/grub/menu.lst Check for a password configuration line, such as: password --md5 <password-hash> If the boot loader passwords are not protected using an MD5 hash or stronger, this is a finding. | Consult vendor documentation for procedures concerning the system's boot loader. Configure the boot loader to hash boot loader passwords using MD5 or a stronger hash. |
| V-27250 | CCI-000293 | medium | A file integrity baseline including cryptographic hashes must be created. | A file integrity baseline is a collection of file metadata which is to evaluate the integrity of the system. A minimal baseline must contain metadata for all device files, setuid files, setgid files, system libraries, system binaries, and system configuration files. The minimal metadata must consist of the mode, owner, group owner, and modification times. For regular files, metadata must also include file size and a cryptographic hash of the file’s contents. | Verify a system integrity baseline exists. The Advanced Intrusion Detection Environment (AIDE) is included in the distribution of RHEL. Other host intrusion detection system (HIDS) software is available but must be checked manually. Procedure: # grep DBDIR /etc/aide.conf If /etc/aide.conf does not exist AIDE has not been installed. Unless another HIDS is used on the system, this is a finding. Examine the response for "database" this indicates the location of the system integrity baseline database used as input to a comparison. # ls -la <DBDIR> If no "database" file as defined in /etc/aide.conf exists a system integrity baseline has not been created, this is a finding. Examine /etc/aide.conf to ensure some form of cryptographic hash (i.e. md5,rmd168,sha256) is used for files. In the default /etc/aide.conf the "NORMAL" or "LSPP" rules which are used for virtually all files DO include some form of cryptographic hash. If the site has defined rules to replace the functionality provided by the default "NORMAL" and "LSPP" rules but DOES NOT include cryptographic hashes, this is a finding. Otherwise, if any element used to define the "NORMAL" and "LSPP" rules has been modified resulting in cryptographic hashes not being used, this is a finding. If any other modification to the default /etc/aide.conf file have been made resulting in rules which do not include cryptographic hashes on appropriate files, this is a finding. | Use AIDE to create a file integrity baseline, including cryptographic hashes, for the system. Configure the /etc/aide.conf file to ensure some form of cryptographic hash (ie. md5,rmd168,sha256) is used for files. In the default /etc/aide.conf the "NORMAL" or "LSPP" rules which are used for virtually all files DO include some form of cryptographic hash. |
| V-27251 | CCI-000293 | medium | A file integrity baseline including cryptographic hashes must be maintained. | A file integrity baseline is a collection of file metadata which is to evaluate the integrity of the system. A minimal baseline must contain metadata for all device files, setuid files, setgid files, system libraries, system binaries, and system configuration files. The minimal metadata must consist of the mode, owner, group owner, and modification times. For regular files, metadata must also include file size and a cryptographic hash of the file’s contents. | Verify a system integrity baseline is maintained. The baseline has been updated to be consistent with the latest approved system configuration changes. The Advanced Intrusion Detection Environment (AIDE) is included in the distribution of RHEL-5. Other host intrusion detection system (HIDS) software is available but must be checked manually. Procedure: # grep DBDIR /etc/aide.conf If /etc/aide.conf does not exist AIDE has not been installed. Unless another HIDS is used on the system, this is a finding. Examine the response for "database" indicates the location of the system integrity baseline database used as input to a comparison. # ls -la <DBDIR> If the no "database" file as defined in /etc/aide.conf a system integrity baseline has not been created, this is a finding. Ask the SA when the last approved system configuration changes occurred. If the modification date of the AIDE database is prior to the last approved configuration change, this is a finding. | Regularly rebuild the integrity baseline, including cryptographic hashes, for the system to be consistent with the latest approved system configuration. Procedure: After an approved modification to the system configuration has been made perform: # aide -u This will update the database. |
| V-27275 | CCI-000012 | medium | The system must not have the unnecessary "news" account. | Accounts that provide no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system. | Check the system for the unnecessary "news" accounts. Procedure: # rpm -q inn If the "inn" is installed the "news" user is necessary and this is not a finding. # grep ^news /etc/passwd If this account exists and "inn" is not installed, this is a finding. | Remove the "news" account from the /etc/passwd file before connecting a system to the network. |
| V-27276 | CCI-000012 | medium | The system must not have the unnecessary "gopher" account. | Accounts that provide no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system. | Check the system for the unnecessary "gopher" accounts. Procedure: # grep ^gopher /etc/passwd If this account exists, it is a finding. | Remove the "gopher" account from the /etc/passwd file before connecting a system to the network. |
| V-27279 | CCI-000012 | medium | The system must not have the unnecessary "ftp" account. | Accounts that provide no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system. | Check the system for the unnecessary "ftp" accounts. Procedure: # rpm -q krb5-workstation An ftp server is part of "krb5-workstation". If it is installed the "ftp" user is necessary and this is not a finding. # rpm -q vsftp If the "vsftp" ftp server is installed the "ftp" user is necessary and this is not a finding. # grep ^ftp /etc/passwd If this account exists and no ftp server is installed which requires it, this is a finding. | Remove the "ftp" account from the /etc/passwd file before connecting a system to the network. |
| V-27283 | CCI-000057 | medium | The graphical desktop environment must set the idle timeout to no more than 15 minutes. | If graphical desktop sessions do not lock the session after 15 minutes of inactivity, requiring re-authentication to resume operations, the system or individual data could be compromised by an alert intruder who could exploit the oversight. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices as well as to graphical desktop environments provided to remote systems, including thin clients. | For the Gnome screen saver, check the idle_delay setting. Procedure: # gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/idle_delay If this does not return 15 or less, this is a finding. | For the Gnome screen saver, set idle_delay to 15. Procedure: # gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type int --set /apps/gnome-screensaver/idle_delay 15 |
| V-27284 | CCI-000057 | medium | Graphical desktop environments provided by the system must have automatic lock enabled. | If graphical desktop sessions do not lock the session after 15 minutes of inactivity, requiring re-authentication to resume operations, the system or individual data could be compromised by an alert intruder who could exploit the oversight. This requirement applies to graphical desktop environments provided by the system to locally attached displays and input devices as well as to graphical desktop environments provided to remote systems, including thin clients. | For the Gnome screen saver, check the lock_enabled flag. Procedure: # gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --get /apps/gnome-screensaver/lock_enabled If this does not return "true", this is a finding. | For the Gnome screen saver, set the lock_enabled flag. Procedure: # gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type bool --set /apps/gnome-screensaver/lock_enabled true |
| V-27285 | CCI-000192 | medium | Global settings defined in system-auth must be applied in the pam.d definition files. | Pam global requirements are generally defined in the /etc/pam.d/system-auth or /etc/pam.d/system-auth-ac file. In order for the requirements to be applied the file containing them must be included directly or indirectly in each program's definition file in /etc/pam.d | Verify the system-auth settings are being applied. Procedure: Verify the additional pam.d requirements are in use. The file "/etc/pam.d/system-auth-ac" is auto generated by "authconfig". Any manual changes made to it will be lost next time "authconfig" is run. Check to see if the systems default of the symlink "/etc/pam.d/system-auth" pointing to "/etc/pam.d/system-auth-ac" has been changed. # ls -l /etc/pam.d/system-auth If the symlink points to "/etc/pam.d/system-auth-ac", manual changes cannot be protected. This is a finding. # grep system-auth-ac /etc/pam.d/system-auth The local system-auth file pointed to by "/etc/pam.d/system-auth" must contain "/etc/pam.d/system-auth-ac" for the auth, account, password, and session lines. If it does not then the parameters maintained by "authconfig" will not be applied, this is a finding. | In the default distribution of RHEL "/etc/pam.d/system-auth" is a symlink "/etc/pam.d/system-auth-ac" which is an autogenerated file. When a site adds password requirements a new system-auth-local file must be created with only the additional requirements and includes for auth, account, passwd and session pointing to "/etc/pam.d/system-auth-ac". Then the symlink "/etc/system-auth" is modified to point to "/etc/pam.d/system-auth-local". This way any changes made do not get lost when "/etc/pam.d/system-auth-ac" is regenerated and each program's pam.d definition file need only have "include system-auth" for auth, account, passwd and session, as needed, in order to assure the password requirements will be applied to it. |
| V-29236 | CCI-000192 | medium | The audit system must be configured to audit failed attempts to access files and programs. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check that auditd is configured to audit failed file access attempts. There must be an audit rule for each of the access syscalls that logs all failed accesses (-F success=0) or there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S open" | grep "-F success=0" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S open" | grep "-F exit=-EPERM" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S open" | grep "-F exit=-EACCES" If an "-S open" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "open" exist, then this is a finding. | Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs: either: -a exit,always -F arch=<ARCH> -S open -F success=0 or both: -a exit,always -F arch=<ARCH> -S open -F exit=-EPERM -a exit,always -F arch=<ARCH> -S open -F exit=-EACCES Restart the auditd service. # service auditd restart |
| V-29237 | CCI-000192 | medium | The audit system must be configured to audit failed attempts to access files and programs. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Verify auditd is configured to audit failed file access attempts. There must be an audit rule for each of the access syscalls logging all failed accesses (-F success=0) or there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S openat" | grep "-F success=0" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S openat" | grep "-F exit=-EPERM" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S openat" | grep "-F exit=-EACCES" If an "-S openat" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "openat" exist, then this is a finding. | Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs: either: -a exit,always -F arch=<ARCH> -S openat -F success=0 or both: -a exit,always -F arch=<ARCH> -S openat -F exit=-EPERM -a exit,always -F arch=<ARCH> -S openat -F exit=-EACCES Restart the auditd service. # service auditd restart |
| V-29238 | CCI-000192 | medium | The audit system must be configured to audit failed attempts to access files and programs. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Verify auditd is configured to audit failed file access attempts. There must be an audit rule for each of the access syscalls logging all failed accesses (-F success=0) or there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S truncate" | grep "-F success=0" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S truncate" | grep "-F exit=-EPERM" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S truncate" | grep "-F exit=-EACCES" If an "-S truncate" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "truncate" exist, then this is a finding. | Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs: either: -a exit,always -F arch=<ARCH> -S truncate -F success=0 or both: -a exit,always -F arch=<ARCH> -S truncate -F exit=-EPERM -a exit,always -F arch=<ARCH> -S truncate -F exit=-EACCES Restart the auditd service. # service auditd restart |
| V-29239 | CCI-000192 | medium | The audit system must be configured to audit failed attempts to access files and programs. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Verify auditd is configured to audit failed file access attempts. There must be an audit rule for each of the access syscalls logging all failed accesses (-F success=0) or there must both an "-F exit=-EPERM" and "-F exit=-EACCES" for each access syscall. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S ftruncate" | grep "-F success=0" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S ftruncate" | grep "-F exit=-EPERM" # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep "-S ftruncate" | grep "-F exit=-EACCES" If an "-S ftruncate" audit rule with "-F success" does not exist and no separate rules containing "-F exit=-EPERM" and "-F exit=-EACCES" for "ftruncate" exist, then this is a finding. | Edit the audit.rules file and add the following line(s) to enable auditing of failed attempts to access files and programs: either: -a exit,always -F arch=<ARCH> -S ftruncate -F success=0 or both: -a exit,always -F arch=<ARCH> -S ftruncate -F exit=-EPERM -a exit,always -F arch=<ARCH> -S ftruncate -F exit=-EACCES Restart the auditd service. # service auditd restart |
| V-29240 | CCI-000126 | medium | The audit system must be configured to audit file deletions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system audit configuration to determine if file and directory deletions are audited. # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "rmdir" If no results are returned, or the results do not contain "-S rmdir", this is a finding. | Edit the audit.rules file and add the following line to enable auditing of deletions: -a exit,always -S rmdir Restart the auditd service. # service auditd restart |
| V-29241 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -i "audit.rules" If no results are returned, or the line does not start with "-w", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions: -w /etc/audit.rules -w /etc/audit/audit.rules Restart the auditd service. # service auditd restart |
| V-29242 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "adjtime" If the result does not contain "-S adjtime", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions: -a exit,always -F arch=<ARCH> -S adjtime Restart the auditd service. # service auditd restart |
| V-29243 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "settimeofday" If the result does not contain "-S settimeofday", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions: -a exit,always -F arch=<ARCH> -S settimeofday Restart the auditd service. # service auditd restart |
| V-29244 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "stime" If the result does not contain "-S stime", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions: -a exit,always -F arch=<ARCH> -S stime Restart the auditd service. # service auditd restart |
| V-29245 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "clock_settime" If the result does not contain "-S clock_settime", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions: -a exit,always -F arch=<ARCH> -S clock_settime Restart the auditd service. # service auditd restart |
| V-29246 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "sethostname" If the result does not contain "-S sethostname", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions: -a exit,always -F arch=<ARCH> -S sethostname Restart the auditd service. # service auditd restart |
| V-29247 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "setdomain" If the result does not contain "-S setdomain", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Add the following lines to the audit.rules file to enable auditing of administrative, privileged, and security actions: -a exit,always -F arch=<ARCH> -S setdomainname Restart the auditd service. # service auditd restart |
| V-29248 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "sched_setparam" If the result does not contain "-S sched_setparam", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: A Real Time Operating System (RTOS) provides specialized system scheduling which causes an inordinate number of messages to be produced when the sched_setparam and set_setscheduler are audited. This not only may degrade the system speed to an unusable level but obscures any forensic information which may otherwise have been useful. Unless the operating system is a Red Hat 5 based RTOS (including MRG and AS5300) the following should also be present in /etc/audit/audit.rules -a exit,always -F arch=<ARCH> -S sched_setparam Restart the auditd service. # service auditd restart |
| V-29249 | CCI-000347 | medium | The audit system must be configured to audit all administrative, privileged, and security actions. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the auditing configuration of the system. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "sched_setscheduler" If the result does not contain "-S sched_setscheduler", this is a finding. | The "-F arch=<ARCH>"restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>"restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: A Real Time Operating System (RTOS) provides specialized system scheduling which causes an inordinate number of messages to be produced when the sched_setparam and set_setscheduler are audited. This not only may degrade the system speed to an unusable level but obscures any forensic information which may otherwise have been useful. Unless the operating system is a Red Hat 5 based RTOS (including MRG and AS5300) the following should also be present in /etc/audit/audit.rules -a exit,always -F arch=<ARCH> -S sched_setscheduler Restart the auditd service. # service auditd restart |
| V-29250 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "fchmod" If "-S fchmod" is not in the result, this is a finding | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S fchmod Restart the auditd service. # service auditd restart |
| V-29251 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "fchmodat" If "-S fchmodat" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S fchmodat Restart the auditd service. # service auditd restart |
| V-29252 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "chown" If "-S chown" is not in the result, this is a finding. Additionally, the following rule is required in systems supporting the 32-bit syscall table (such as i686 and x86_64): # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "chown32" If "-S chown32" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S chown Additionally, the following rule is required in systems supporting the 32-bit syscall table (such as i686 and x86_64): -a exit,always -F arch=<ARCH> -S chown32 Restart the auditd service. # service auditd restart |
| V-29253 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "fchown" If "-S fchown" is not in the result, this is a finding. Additionally, the following rule is required in systems supporting the 32-bit syscall table (such as i686 and x86_64): # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "fchown32" If "-S fchown32" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S fchown Additionally, the following rule is required in systems supporting the 32-bit syscall table (such as i686 and x86_64): -a exit,always -F arch=<ARCH> -S fchown32 Restart the auditd service. # service auditd restart |
| V-29255 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "fchownat" If "-S fchownat" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S fchownat Restart the auditd service. # service auditd restart |
| V-29257 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "lchown" If "-S lchown" is not in the result, this is a finding. Additionally, the following rule is required in systems supporting the 32-bit syscall table (such as i686 and x86_64): # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "lchown32" If "-S lchown32" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S lchown Additionally, the following rule is required in systems supporting the 32-bit syscall table (such as i686 and x86_64): -a exit,always -F arch=<ARCH> -S lchown32 Restart the auditd service. # service auditd restart |
| V-29259 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "setxattr" If "-S setxattr" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S setxattr Restart the auditd service. # service auditd restart |
| V-29261 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "lsetxattr" If "-S lsetxattr" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S lsetxattr Restart the auditd service. # service auditd restart |
| V-29272 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "fsetxattr" If "-S fsetxattr" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S fsetxattr Restart the auditd service. # service auditd restart |
| V-29274 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "removexattr" If "-S removexattr" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S removexattr Restart the auditd service. # service auditd restart |
| V-29275 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "lremovexattr" If "-S lremovexattr" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S lremovexattr Restart the auditd service. # service auditd restart |
| V-29279 | CCI-000126 | medium | The audit system must be configured to audit all discretionary access control permission modifications. | If the system is not configured to audit certain activities and write them to an audit log, it is more difficult to detect and track system compromises and damages incurred during a system compromise. | Check the system's audit configuration. Procedure: # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "fremovexattr" If "-S fremovexattr" is not in the result, this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Edit the audit.rules file and add the following lines to enable auditing of discretionary access control permissions modifications. -a exit,always -F arch=<ARCH> -S fremovexattr Restart the auditd service. # service auditd restart |
| V-29281 | CCI-000126 | medium | The audit system must be configured to audit the loading and unloading of dynamic kernel modules - delete_module. | Actions concerning dynamic kernel modules must be recorded as they are substantial events. Dynamic kernel modules can increase the attack surface of a system. A malicious kernel module can be used to substantially alter the functioning of a system, often with the purpose of hiding a compromise from the SA. | Determine if the delete_module syscall is audited. # cat /etc/audit/audit.rules | grep -e "-a exit,always" | grep -i "delete_module" If the result does not contain "-S delete_module", this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Configure auditing of the delete_module syscalls. Add the following to the "etc/audit/audit.rules" or "etc/audit.rules" file: -a exit,always -S delete_module Restart the auditd service. # service auditd restart |
| V-29284 | CCI-000126 | medium | The audit system must be configured to audit the loading and unloading of dynamic kernel modules - /sbin/insmod. | Actions concerning dynamic kernel modules must be recorded as they are substantial events. Dynamic kernel modules can increase the attack surface of a system. A malicious kernel module can be used to substantially alter the functioning of a system, often with the purpose of hiding a compromise from the SA. | Determine if /sbin/insmod is audited. # cat /etc/audit/audit.rules | grep "/sbin/insmod" If the result does not start with "-w" and contain "-p x", this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Configure auditing of the /sbin/insmod, files. Add the following to the "etc/audit/audit.rules" or "etc/audit.rules" file: -w /sbin/insmod -p x Restart the auditd service. # service auditd restart |
| V-29286 | CCI-000126 | medium | The audit system must be configured to audit the loading and unloading of dynamic kernel modules -/sbin/modprobe. | Actions concerning dynamic kernel modules must be recorded as they are substantial events. Dynamic kernel modules can increase the attack surface of a system. A malicious kernel module can be used to substantially alter the functioning of a system, often with the purpose of hiding a compromise from the SA. | Determine if the /sbin/modprobe file is audited. # cat /etc/audit/audit.rules | grep "/sbin/modprobe" If the result does not start with "-w" and contain "-p x", this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: -w /sbin/modprobe -p x Restart the auditd service. # service auditd restart |
| V-29288 | CCI-000126 | medium | The audit system must be configured to audit the loading and unloading of dynamic kernel modules - /sbin/rmmod | Actions concerning dynamic kernel modules must be recorded as they are substantial events. Dynamic kernel modules can increase the attack surface of a system. A malicious kernel module can be used to substantially alter the functioning of a system, often with the purpose of hiding a compromise from the SA. | Determine if the /sbin/rmmod file is audited. # cat /etc/audit/audit.rules | grep "/sbin/rmmod" If the result does not start with "-w" and contain "-p x", this is a finding. | The "-F arch=<ARCH>" restriction is required on dual-architecture systems (such as x86_64). On dual-architecture systems, two separate rules must exist - one for each architecture supported. Use the generic architectures "b32" and "b64" for specifying these rules. On single architecture systems, the "-F arch=<ARCH>" restriction may be omitted, but if present must match either the architecture of the system or its corresponding generic architecture. The architecture of the system may be determined by running "uname -m". See the auditctl(8) manpage for additional details. Any restrictions (such as with "-F") beyond those provided in the example rules are not in strict compliance with this requirement, and are a finding unless justified and documented appropriately. The use of audit keys consistent with the provided example is encouraged to provide for uniform audit logs, however omitting the audit key or using an alternate audit key is not a finding. Procedure: Configure auditing of the /sbin/rmmod file. Add the following to the "etc/audit/audit.rules" or "etc/audit.rules" file: -w /sbin/rmmod -p x Restart the auditd service. # service auditd restart |
| V-29289 | CCI-000225 | medium | Files in cron script directories must have mode 0700 or less permissive. | To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured. | Check the mode of scripts in cron job directories. # ls -lL /etc/cron.daily/ # ls -lL /etc/cron.hourly/ # ls -lL /etc/cron.monthly/ # ls -lL /etc/cron.weekly/ If any cron script has a mode more permissive than 0700, this is a finding. | Change the mode of the cron scripts. # chmod 0700 /etc/cron.daily/* /etc/cron.hourly/* /etc/cron.monthly/* /etc/cron.weekly/* |
| V-29376 | CCI-000012 | medium | The system must not have the unnecessary "games" account. | Accounts that provide no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system. | Check the system for the unnecessary "games" accounts. Procedure: # grep ^games /etc/passwd If this account exists, it is a finding. | Remove the "games" account. Procedure: # userdel games |
| V-760 | CCI-000770 | medium | Direct logins must not be permitted to shared, default, application, or utility accounts. | Shared accounts (accounts where two or more people log in with the same user identification) do not provide identification and authentication. There is no way to provide for non-repudiation or individual accountability. | Use the last command to check for multiple accesses to an account from different workstations/IP addresses. # last -R If users log directly onto accounts, rather than using the switch user (su) command from their own named account to access them, this is a finding (such as logging directly on to oracle). Verify with the SA or the IAO on documentation for users/administrators to log into their own accounts first and then switch user (su) to the account to be shared has been maintained including requirements and procedures. If no such documentation exists, this is a finding. | Use the switch user (su) command from a named account login to access shared accounts. Document requirements and procedures for users/administrators to log into their own accounts first and then switch user (su) to the account to be shared. |
| V-762 | CCI-000764 | medium | All accounts must be assigned unique User Identification Numbers (UIDs). | Accounts sharing a UID have full access to each others' files. This has the same effect as sharing a login. There is no way to assure identification, authentication, and accountability because the system sees them as the same user. If the duplicate UID is 0, this gives potential intruders another privileged account to attack. | Perform the following to ensure there are no duplicate UIDs: # cut -d: -f3 /etc/passwd | uniq -d If any duplicate UIDs are found, this is a finding. | Edit user accounts to provide unique UIDs for each account. |
| V-766 | CCI-000044 | medium | The system must disable accounts after three consecutive unsuccessful login attempts. | Disabling accounts after a limited number of unsuccessful login attempts improves protection against password guessing attacks. | Check the pam_tally configuration. # more /etc/pam.d/system-auth Confirm the following line is configured, before any "auth sufficient" lines: auth required pam_tally2.so deny=3 If no such line is found, this is a finding. | By default link /etc/pam.d/system-auth points to /etc/pam.d/system-auth-ac which is the file maintained by the authconfig utility. In order to add pam options other than those available via the utility create /etc/pam.d/system-auth-local with the options and including system-auth-ac. In order to set the account lockout to three failed attempts the content should be similar to: auth required pam_access.so auth required pam_tally2.so deny=3 auth include system-auth-ac account required pam_tally2.so account include system-auth-ac password include system-auth-ac session include system-auth-ac Once system-auth-local is written reset the /etc/pam.d/system-auth to point to system-auth-local. This is necessary because authconfig writes directly to system-auth-ac so any changes made by hand will be lost if authconfig is run. |
| V-768 | CCI-000043 | medium | The delay between login prompts following a failed login attempt must be at least 4 seconds. | Enforcing a delay between successive failed login attempts increases protection against automated password guessing attacks. | Check the value of the FAIL_DELAY variable and the ability to use it. Procedure: # grep FAIL_DELAY /etc/login.defs If the value does not exist, or is less than 4, this is a finding. Check for the use of pam_faildelay. # grep pam_faildelay /etc/pam.d/system-auth* If pam_faildelay.so module is not present, this is a finding. If pam_faildelay is present only in /etc/pam.d/system-auth-ac: ensure that /etc/pam.d/system-auth includes /etc/pam.d/system-auth-ac. #grep system-auth-ac /etc/pam.d/system-auth This should return: auth include system-auth-ac account include system-auth-ac password include system-auth-ac session include system-auth-ac /etc/pam.d/system-auth-ac should only be included by /etc/pam.d/system-auth. All other pam files should include /etc/pam.d/system-auth. If pam_faildelay is not defined in /etc/pam.d/system-auth either directly or through inclusion of system-auth-ac, this is a finding. | Add the pam_faildelay module and set the FAIL_DELAY variable. Procedure: Edit /etc/login.defs and set the value of the FAIL_DELAY variable to 4 or more. The default link /etc/pam.d/system-auth points to /etc/pam.d/system-auth-ac which is the file maintained by the authconfig utility. In order to add pam options other than those available via the utility create or modify /etc/pam.d/system-auth-local with the options and including system-auth-ac. For example: auth required pam_access.so auth optional pam_faildelay.so delay=4000000 auth include system-auth-ac account include system-auth-ac password include system-auth-ac session include system-auth-ac Once system-auth-local is written ensure the /etc/pam.d/system-auth points to system-auth-local. This is necessary because authconfig writes directly to system-auth-ac so any manual changes made will be lost if authconfig is run. |
| V-778 | CCI-000770 | medium | The system must prevent the root account from directly logging in except from the system console. | Limiting the root account direct logins to only system consoles protects the root account from direct unauthorized access from a non-console device. | Check /etc/securetty # more /etc/securetty If the file does not exist, or contains more than "console" or a single "tty" device this is a finding. | Create if needed and set the contents of /etc/securetty to a "console" or "tty" device. # echo console > /etc/securetty or # echo tty1 > /etc/securetty |
| V-810 | CCI-000178 | medium | Default system accounts must be disabled or removed. | Vendor accounts and software may contain backdoors allowing unauthorized access to the system. These backdoors are common knowledge and present a threat to system security if the account is not disabled. | Determine if default system accounts (such as those for sys, bin, uucp, nuucp, daemon, smtp) have been disabled. # cat /etc/shadow If an account's password field (which is the second field in the /etc/shadow file) is "*", "*LK*", or is prefixed with a '!', the account is locked or disabled. If there are any unlocked default system accounts this is a finding. | Lock the default system account(s). # passwd -l <user> |
| V-811 | CCI-000169 | medium | Auditing must be implemented. | Without auditing, individual system accesses cannot be tracked and malicious activity cannot be detected and traced back to an individual account. | Determine if auditing is enabled. # ps -ef |grep auditd If the auditd process is not found, this is a finding. | Start the auditd service and set it to start on boot. # service auditd start ; chkconfig auditd on |