# Cis Ubuntu1604 V200 1 4 4

> Ensure authentication required for single user mode

- Skill: `cyberstrikeus/cis-ubuntu1604-v200-1-4-4` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1604-v200-1-4-4`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1604-v200-1-4-4/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-ubuntu1604-v200-1-4-4

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# CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - 1.4.4

## Profile Applicability

- Level 1 - Server
- Level 1 - Workstation

## Description

Single user mode is used for recovery when the system detects an issue during boot or by manual selection from the bootloader.

## Rationale

Requiring authentication in single user mode prevents an unauthorized user from rebooting the system into single user to gain root privileges without credentials.

## Audit Procedure

### Command Line

Perform the following to determine if a password is set for the root user:

```bash
grep -Eq '^root:\$[0-9]' /etc/shadow || echo "root is locked"
```

No results should be returned.

## Expected Result

The command should return no output, indicating root has a password set. If "root is locked" is returned, root does not have a password set.

## Remediation

### Command Line

Run the following command and follow the prompts to set a password for the root user:

```bash
passwd root
```

## Default Value

Not applicable.

## References

None.

## CIS Controls

| Controls Version | Control                             |
| ---------------- | ----------------------------------- |
| v7               | 5.1 Establish Secure Configurations |

## Assessment Status

Automated