IBM z/OS must employ a session manager that conceal, via the session lock, information previously visible on the display with a publicly viewable image.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-223575	ACF2-OS-002350	SV-223575r533198_rule		Medium

Description
A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. The operating system session lock event must include an obfuscation of the display screen so as to prevent other users from reading what was previously displayed. Publicly viewable images can include static or dynamic images, for example, patterns used with screen savers, photographic images, solid colors, a clock, a battery life indicator, or a blank screen, with the additional caveat that none of the images convey sensitive information.

Description

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. The operating system session lock event must include an obfuscation of the display screen so as to prevent other users from reading what was previously displayed. Publicly viewable images can include static or dynamic images, for example, patterns used with screen savers, photographic images, solid colors, a clock, a battery life indicator, or a blank screen, with the additional caveat that none of the images convey sensitive information.

STIG	Date
IBM z/OS ACF2 Security Technical Implementation Guide	2023-06-16

Details

Check Text ( C-25248r500860_chk )
Ask the system administrator for the configuration parameters for the session manager in use. If there is no session manager in use, this is a finding. If the session manager is not configured to conceal, via the session lock, information previously visible on the display with a publicly viewable image, this is a finding.

Fix Text (F-25236r500861_fix)
Configure the session manager to conceal, via the session lock, information previously visible on the display with a publicly viewable image.