CMMC Practice AC.L2-3.1.10 – Session Lock: Use session lock with pattern-hiding displays to prevent access and viewing of data after a period of inactivity.
Links to Publicly Available Resources
Discussion [NIST SP 800-171 R2]
Session locks are temporary actions taken when users stop work and move away from the immediate vicinity of the system but do not want to log out because of the temporary nature of their absences. Session locks are implemented where session activities can be determined, typically at the operating system level (but can also be at the application level). Session locks are not an acceptable substitute for logging out of the system, for example, if organizations require users to log out at the end of the workday.
Pattern-hiding displays can include static or dynamic images, for example, patterns used with screen savers, photographic images, solid colors, clock, battery life indicator, or a blank screen, with the additional caveat that none of the images convey controlled unclassified information.
Session locks can be initiated by the user or, more fundamentally, enabled automatically when the system has been idle for a period of time, for example, five minutes. Session locks are a quick way to prevent unauthorized use of the systems without having a user log off. Minimum configuration requirements are left up to the organization to define.
A locked session shows pattern-hiding information on the screen to mask the data on the display.