4.1.3.14 Ensure events that modify the system's Mandatory Access Controls are collected

Information

Monitor SELinux, an implementation of mandatory access controls. The parameters below monitor any write access (potential additional, deletion or modification of files in the directory) or attribute changes to the /etc/selinux/ and /usr/share/selinux/ directories.

Note: If a different Mandatory Access Control method is used, changes to the corresponding directories should be audited.

Rationale:

Changes to files in the /etc/selinux/ and /usr/share/selinux/ directories could indicate that an unauthorized user is attempting to modify access controls and change security contexts, leading to a compromise of the system.

Solution

Edit or create a file in the /etc/audit/rules.d/ directory, ending in .rules extension, with the relevant rules to monitor events that modify the system's Mandatory Access Controls.
Example:

# printf '
-w /etc/selinux -p wa -k MAC-policy
-w /usr/share/selinux -p wa -k MAC-policy
' >> /etc/audit/rules.d/50-MAC-policy.rules

Merge and load the rules into active configuration:

# augenrules --load

Check if reboot is required.

# if [[ $(auditctl -s | grep 'enabled') =~ '2' ]]; then printf 'Reboot required to load rules
'; fi

Additional Information:

Potential reboot required

If the auditing configuration is locked (-e 2), then augenrules will not warn in any way that rules could not be loaded into the running configuration. A system reboot will be required to load the rules into the running configuration.

System call structure

For performance (man 7 audit.rules) reasons it is preferable to have all the system calls on one line. However, your configuration may have them on one line each or some other combination. This is important to understand for both the auditing and remediation sections as the examples given are optimized for performance as per the man page.

See Also

https://workbench.cisecurity.org/files/3807