Vulnerability Discussion

The audit system must be configured to record enforcement actions of
attempts to modify file attributes (fm).

Enforcement actions are the methods or mechanisms used to prevent unauthorized changes to configuration
settings. One common and effective enforcement action method is using access restrictions (i.e.,
modifications to a file by applying file permissions).

This configuration ensures that audit lists include events in which enforcement actions attempts to
modify a file.

Without auditing the enforcement of access restrictions, it is difficult to identify attempted attacks,
as there is no audit trail 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-000462-GPOS-00206,SRG-OS-000463-GPOS-00207,SRG-OS-000465-GPOS-00209,SRG-OS-000466-GPOS-00210,SRG-OS-000467-GPOS-00211,SRG-OS-000468-GPOS-00212

Check

Verify the macOS system is configured to audit all changes of object attributes with the
following command:

/usr/bin/awk -F':' '/^flags/ { print $NF }' /etc/security/audit_control | /usr/bin/tr ',' '\n' |
/usr/bin/grep -Ec '^fm'

If the result is not "1", this is a finding.

Fix

Configure the macOS system to audit all changes of object attributes
with the following command:

/usr/bin/grep -qE "^flags.*fm" /etc/security/audit_control || /usr/bin/sed -i.bak '/^flags/ s/$/,fm/'
/etc/security/audit_control;/usr/sbin/audit -s