cis-ubuntu1604-v200-1-8-2

DevOps & Security

Ensure GDM login banner is configured

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_16.04_LTS_Benchmark_v2.0.0/cis-ubuntu1604-v200-1-8-2/SKILL.md

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CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - 1.8.2

Profile Applicability

Level 1 - Server
Level 1 - Workstation

Description

GDM is the GNOME Display Manager which handles graphical login for GNOME based systems.

Rationale

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.

Audit Procedure

Command Line

If GDM is installed on the system verify that /etc/gdm3/greeter.dconf-defaults file exists and contains the following:

[org/gnome/login-screen]
banner-message-enable=true
banner-message-text='<banner message>'

Expected Result

The GDM login banner should be enabled with an appropriate banner message.

Remediation

Command Line

Edit or create the file /etc/gdm3/greeter.dconf-defaults and add the following:

[org/gnome/login-screen]
banner-message-enable=true
banner-message-text='<banner message>'
disable-user-list=true

Example banner message: 'Authorized uses only. All activity may be monitored and reported.'

Run the following command to re-load GDM on the next login or reboot:

dpkg-reconfigure gdm3

Additional Information

Additional options and sections may appear in the /etc/dconf/db/gdm.d/01-banner-message file.

If a different GUI login service is in use, consult your documentation and apply an equivalent banner.

Default Value

Not applicable.

References

None.

CIS Controls

Controls Version	Control
v7	5.1 Establish Secure Configurations

Assessment Status

Automated