InformationDebian defaults to using GNOME Display Manager for graphical login session managemen. KDM is also available as well as lightdm. Instructions are provided for GDM only, if you are using another display manager you will need to follow different procedures to audit and remediate this setting. Warning messages inform users who are attempting to login to the system of their legal status regarding the system and must include the name of the organization that owns the system and any monitoring policies that are in place. Consult with your organization's legal counsel for the appropriate wording for your specific organization.
SolutionUncomment or add the following lines to /etc/gdm3/greeter.gsettings- banner-message-enable=truebanner-message-text='<banner-text>'