Vulnerability Discussion

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 want to log out because of the temporary nature of the absence.

The session lock is implemented at the point where session activity can be determined.

Regardless of where the session lock is determined and implemented, once invoked, the session lock must remain in place until the user re-authenticates. No other activity aside from re-authentication must unlock the system.

Check

Note: This requirement assumes the use of the AlmaLinux OS 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable.

Verify AlmaLinux OS 9 enables a user's session lock until that user re-establishes access using established identification and authentication procedures with the following command:

$ grep -R removal-action= /etc/dconf/db/*

/etc/dconf/db/distro.d/00-security-settings:removal-action='lock-screen'

If the "removal-action='lock-screen'" setting is missing or commented out from the dconf database files, this is a finding.

Fix

Configure AlmaLinux OS 9 to enable a user's session lock until that user re-establishes access using established identification and authentication procedures.

Select or create an authselect profile and incorporate the "with-smartcard-lock-on-removal" feature with the following example:

$ authselect select sssd with-smartcard with-smartcard-lock-on-removal

Alternatively, the dconf settings can be edited in the /etc/dconf/db/* location.

Add or update the [org/gnome/settings-daemon/peripherals/smartcard] section of the /etc/dconf/db/local.d/00-security-settings" database file and add or update the following lines:

[org/gnome/settings-daemon/peripherals/smartcard]
removal-action='lock-screen'

Then update the dconf system databases:

$ dconf update