# Cis Ubuntu1804 V220 1 3 3

> Ensure GPG keys are configured

- Skill: `cyberstrikeus/cis-ubuntu1804-v220-1-3-3` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1804-v220-1-3-3`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1804-v220-1-3-3/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-ubuntu1804-v220-1-3-3

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# 1.3.3 Ensure GPG keys are configured (Manual)

## Profile Applicability

- Level 1 - Server
- Level 1 - Workstation

## Description

Most packages managers implement GPG key signing to verify package integrity during installation.

## Rationale

It is important to ensure that updates are obtained from a valid source to protect against spoofing that could lead to the inadvertent installation of malware on the system.

## Audit Procedure

### Command Line

Verify GPG keys are configured correctly for your package manager:

```bash
apt-key list
```

## Expected Result

GPG keys should be properly configured according to site policy.

## Remediation

### Command Line

Update your package manager GPG keys in accordance with site policy.

## References

1. NIST SP 800-53 Rev. 5: SI-2

## CIS Controls

| Controls Version | Control                                                      | IG 1 | IG 2 | IG 3 |
| ---------------- | ------------------------------------------------------------ | ---- | ---- | ---- |
| v8               | 7.3 Perform Automated Operating System Patch Management      | X    | X    | X    |
| v7               | 3.4 Deploy Automated Operating System Patch Management Tools | X    | X    | X    |
| v7               | 3.5 Deploy Automated Software Patch Management Tools         | X    | X    | X    |

## MITRE ATT&CK Mappings

| Techniques / Sub-techniques | Tactics | Mitigations |
| --------------------------- | ------- | ----------- |
| T1195, T1195.001, T1195.002 | TA0001  | M1051       |