Details
Setting an inactivity interval for the screensaver prevents unauthorized persons from viewing a system left unattended for an extensive period of time.
Solution
Perform the following to implement the prescribed state:
Open System Preferences
Select Desktop & Screen Saver
Select Screen Saver
Set Start after to 20 minutes or less
Alternatively:
In Terminal, run one of the the following commands:
/usr/bin/defaults -currentHost write com.apple.screensaver idleTime -int 600
/usr/bin/defaults -currentHost write com.apple.screensaver idleTime -int 1200
There are anomalies if the command line is used make the setting something other than what is available in the GUI Menu. Choose either 10 minutes or 20 minutes.
Supportive Information
The following resource is also helpful.
This security hardening control applies to the following category of controls within NIST 800-53: Access Control.This control applies to the following type of system Unix.