2.4.1 Ensure an Inactivity Interval of 20 Minutes Or Less for the Screen Saver Is Enabled

Information

A locking screen saver is one of the standard security controls to limit access to a computer and the current user's session when the computer is temporarily unused or unattended. In macOS, the screen saver starts after a value is selected in the drop-down menu. 20 minutes or less is an acceptable value. Any value can be selected through the command line or script, but a number that is not reflected in the GUI can be problematic. 20 minutes is the default for new accounts.

Setting an inactivity interval for the screen saver prevents unauthorized persons from viewing a system left unattended for an extensive period of time.

Solution

Run the following command to verify that the idle time of the screen saver to 20 minutes of less (<=1200)

% sudo -u <username> defaults -currentHost write com.apple.screensaver idleTime -int <value <=1200>

Note:

Issues arise if the command line is used to make the setting something other than what is available in the GUI Menu. The GUI allows the options of 1 (60), 2 (120), 5 (300), 10 (600), or 20 (120) minutes, so use one of those values to avoid any issues.

Impact:

If the screen saver is not set, users may leave the computer available for an unauthorized person to access information.

See Also

https://workbench.cisecurity.org/benchmarks/17465