Cis Ubuntu1604 V200 1 8 2

---
name: cis-ubuntu1604-v200-1-8-2
description: "Ensure GDM login banner is configured"
category: cis-iam
version: "2.0.0"
author: cyberstrike-official
tags: [cis, ubuntu, linux, ubuntu-16.04, gdm, gnome, banner, login, display-manager]
cis_id: "1.8.2"
cis_benchmark: "CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0"
tech_stack: [ubuntu, linux]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---

# 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:

```bash
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