# Cis GCP Cos 5.1.18

> Ensure SSH warning banner is configured

- Skill: `cyberstrikeus/cis-gcp-cos-5-1-18` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-gcp-cos-5-1-18`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-gcp-cos-5-1-18/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-gcp-cos-5-1-18

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# 5.1.18 Ensure SSH warning banner is configured (Automated)

## Description

The `Banner` parameter specifies a file whose contents must be sent to the remote user before authentication is permitted. By default, no banner is displayed.

## Rationale

Banners are used to warn connecting users of the particular site's policy regarding connection. Presenting a warning message prior to the normal user login may assist the prosecution of trespassers on the computer system.

## Audit Procedure

Run the following command and verify that output matches:

```bash
# sshd -T | grep banner

Banner /etc/issue.net
```

## Expected Result

Output should show `Banner /etc/issue.net`.

## Remediation

Edit the `/etc/ssh/sshd_config` file to set the parameter as follows:

```
Banner /etc/issue.net
```

## CIS Controls

| Controls Version | Control                             | IG 1 | IG 2 | IG 3 |
| ---------------- | ----------------------------------- | ---- | ---- | ---- |
| v7               | 5.1 Establish Secure Configurations | x    | x    | x    |

## Profile

- Level 2 - Server