Title

The macOS system must provide an immediate warning to the System Administrator (SA) and Information System Security Officer (ISSO) (at a minimum) when allocated audit record storage volume reaches 75 percent of repository maximum audit record storage capacity. (Cat III impact)

Discussion

The audit service must be configured to require a minimum percentage of free disk space to run. This ensures that audit will notify the administrator that action is required to free up more disk space for audit logs. When "minfree" is set to 25 percent, security personnel are notified immediately when the storage volume is 75 percent full and are able to plan for audit record storage capacity expansion.

Check Content

Verify the macOS system is configured to require a minimum of 25 percent free disk space for audit record storage with the following command: /usr/bin/sudo /usr/bin/grep ^minfree /etc/security/audit_control minfree:25 If "minfree" is not set to "25", this is a finding.

Fix Text

Configure the macOS system to require 25 percent free disk space for audit record storage with the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/.*minfree.*/minfree:25/' /etc/security/audit_control; /usr/bin/sudo /usr/sbin/audit -s Alternatively, use a text editor to update the "/etc/security/audit_control" file.

Additional Identifiers

Rule ID: SV-257180r905173_rule

Vulnerability ID: V-257180

Group Title: SRG-OS-000343-GPOS-00134

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.