Vulnerability Discussion
The audit system must be configured to record enforcement actions of access restrictions, including failed file read (-fr) attempts.
Enforcement actions are the methods or mechanisms used to prevent unauthorized access and/or changes to configuration settings. One common and effective enforcement action method is using access restrictions (e.g., denying access to a file by applying file permissions).
This configuration ensures that audit lists include events in which enforcement actions prevent attempts to read a file.
Without auditing the enforcement of access restrictions, it is difficult to identify attempted attacks because no audit trail is available for forensic investigation.
Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000064-GPOS-00033, SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000474-GPOS-00219
Check
Verify the macOS system is configured to audit all failed read actions on the system with the following command:
/usr/bin/awk -F':' '/^flags/ { print $NF }' /etc/security/audit_control | /usr/bin/tr ',' '\n' | /usr/bin/grep -Ec '\-fr'
If the result is not "1", this is a finding.
Fix
Configure the macOS system to audit all failed read actions on the system with the following command:
/usr/bin/grep -qE "^flags.*-fr" /etc/security/audit_control || /usr/bin/sed -i.bak '/^flags/ s/$/,-fr/' /etc/security/audit_control;/usr/sbin/audit -s