Details
The intent of this control is to resemble control-alt-delete on Windows Systems as a means of quickly locking the screen. If the user of the system is stepping away from the computer the best practice is to lock the screen and setting a hot corner is an appropriate method.
Rationale:
Ensuring the user has a quick method to lock their screen may reduce opportunity for individuals in close physical proximity of the device to see screen contents.
Solution
In System Preferences: Desktop & Screen Saver: Screen Saver: Hot Corners, make sure at least one Active Screen Corner is set to Start Screen Saver. Make sure the user knows about this feature.
The screen corners can be set using the defaults command, but the permutations of combinations are many. The plist file to check is ~/Library/Preferences/com.apple.dock and the keys are
wvous-bl-corner
wvous-br-corner
wvous-tl-corner
wvous-tr-corner
There are also modifier keys to check and various values for each of these keys. A value of 5 means the corner will start the screen saver. The corresponding wvous-xx-modifier key should be set to 0.
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.