# CIS Ubuntu 14.04 LTS - 6.2.20 Ensure shadow group is empty

> Verify the shadow group has no users assigned to it

- Skill: `cyberstrikeus/cis-ubuntu-14-04-lts-6-2-20-ensure-shadow-group-is-empty` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu-14-04-lts-6-2-20-ensure-shadow-group-is-empty`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu-14-04-lts-6-2-20-ensure-shadow-group-is-empty/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector CAUTION)
- 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-ubuntu-14-04-lts-6-2-20-ensure-shadow-group-is-empty

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# 6.2.20 Ensure shadow group is empty (Scored)

## Profile Applicability

- Level 1 - Server
- Level 1 - Workstation

## Description

The shadow group allows system programs which require access the ability to read the /etc/shadow file. No users should be assigned to the shadow group.

## Rationale

Any users assigned to the shadow group would be granted read access to the /etc/shadow file. If attackers can gain read access to the `/etc/shadow` file, they can easily run a password cracking program against the hashed passwords to break them. Other security information that is stored in the `/etc/shadow` file (such as expiration) could also be useful to subvert additional user accounts.

## Audit Procedure

Run the following commands and verify no results are returned:

```bash
grep ^shadow:[^:]*:[^:]*:[^:]+ /etc/group
awk -F: '($4 == "<shadow-gid>") { print }' /etc/passwd
```

## Expected Result

No output should be returned.

## Remediation

Remove all users from the shadow group, and change the primary group of any users with shadow as their primary group.

## Default Value

The shadow group is empty by default.

## References

None

## CIS Controls

5.1 Minimize And Sparingly Use Administrative Privileges - Minimize administrative privileges and only use administrative accounts when they are required. Implement focused auditing on the use of administrative privileged functions and monitor for anomalous behavior.

## Profile

- Level 1