NIST Special Publication 800-53 (Rev. 4)

Security and Privacy Controls for Federal Information Systems and Organizations


Access Control
P3 - Implement P3 security controls after implementation of P1 and P2 controls.
Baseline Allocation:
Low Moderate High
AC-11 (1)
AC-11 (1)

Control Description

The information system:

a. Prevents further access to the system by initiating a session lock after [Assignment: organization-defined time period] of inactivity or upon receiving a request from a user; and

b. Retains the session lock until the user reestablishes access using established identification and authentication procedures.

Supplemental Guidance

Session locks are temporary actions taken when users stop work and move away from the immediate vicinity of information systems 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. This is 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 information systems, for example, if organizations require users to log out at the end of workdays.

Related to: AC-7

Control Enhancements

The information system conceals, via the session lock, information previously visible on the display with a publicly viewable image.
Supplemental Guidance: Publicly viewable images 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 sensitive information.