Information
Successful/unsuccessful uses of setsebool must generate an audit record.
Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information.
At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The "setsebool" command sets the current state of a particular SELinux boolean or a list of booleans to a given value.
When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way.
Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
Solution
Configure the audit system to generate an audit event for any successful/unsuccessful use of the setsebool command by adding or updating the following rule in a .rules file in the /etc/audit/rules.d/ directory:
-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update
Example:
#!/usr/bin/env bash
{
UID_MIN=$(awk '/^\s*UID_MIN/{print $2}' /etc/login.defs)
[ -n "${UID_MIN}" ] && printf '\n%s\n' \
"-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=${UID_MIN} -F auid!=unset -k privileged-unix-update" \
>> /etc/audit/rules.d/50-privileged-unix-update.rules || printf "ERROR: Variable 'UID_MIN' is unset.\n"
}
Run the following command to merge and load the rules into active configuration:
# augenrules --load
Run the following command to check if reboot is required.
# if [[ $(auditctl -s | grep "enabled") =~ "2" ]]; then printf "Reboot required to load rules\n"; fi