# Cis Ubuntu1204 V110 12 5

> Verify User/Group Ownership on /etc/shadow

- Skill: `cyberstrikeus/cis-ubuntu1204-v110-12-5` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1204-v110-12-5`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1204-v110-12-5/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-ubuntu1204-v110-12-5

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# 12.5 Verify User/Group Ownership on /etc/shadow (Scored)

## Profile Applicability

- Level 1

## Description

The `/etc/shadow` file contains the one-way cipher text passwords for each user defined in the `/etc/passwd` file. The command below sets the user and group ownership of the file to root.

## Rationale

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

## Audit Procedure

### Using Command Line

Run the following command to determine the ownership of the `/etc/shadow` file. Ensure it is owned by user root, and group root or shadow.

```bash
/bin/ls -l /etc/shadow
```

## Expected Result

```
-rw-r----- 1 root shadow <size> <date> shadow
```

Owner should be `root` and group should be `root` or `shadow`.

## Remediation

### Using Command Line

If the ownership of the `/etc/shadow` file is incorrect, run the following command to correct them:

```bash
/bin/chown root:shadow /etc/shadow
```

## Default Value

root:shadow

## References

- CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0

## Profile

Level 1 - Scored