Vulnerability Discussion

Setting the screensaver mode to blank-only conceals the contents of the display from passersby.

Check

To ensure the screensaver is configured to be blank, run the following command:

Note: This requirement assumes the use of the RHEL 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.

$ gsettings get org.gnome.desktop.screensaver picture-uri

If properly configured, the output should be "''".

To ensure that users cannot set the screensaver background, run the following:

$ grep picture-uri /etc/dconf/db/local.d/locks/*

If properly configured, the output should be "/org/gnome/desktop/screensaver/picture-uri".

If it is not set or configured properly, this is a finding.

Fix

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

First, add or update the [org/gnome/desktop/screensaver] section of the "/etc/dconf/db/local.d/00-security-settings" database file and add or update the following lines:

[org/gnome/desktop/screensaver]
picture-uri=''

Then, add the following line to "/etc/dconf/db/local.d/locks/00-security-settings-lock" to prevent user modification:

/org/gnome/desktop/screensaver/picture-uri

Finally, update the dconf system databases:

$ sudo dconf update