# Cis Ubuntu1604 V200 5 3 9

> Ensure SSH IgnoreRhosts is enabled

- Skill: `cyberstrikeus/cis-ubuntu1604-v200-5-3-9` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1604-v200-5-3-9`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1604-v200-5-3-9/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-ubuntu1604-v200-5-3-9

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# CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Control 5.3.9

## Description

The `IgnoreRhosts` parameter specifies that `.rhosts` and `.shosts` files will not be used in `RhostsRSAAuthentication` or `HostbasedAuthentication`.

## Rationale

Setting this parameter forces users to enter a password when authenticating with ssh.

## Audit Procedure

### Command Line

Run the following command and verify that output matches:

```bash
sshd -T -C user=root -C host="$(hostname)" -C addr="$(grep $(hostname) /etc/hosts | awk '{print $1}')" | grep ignorerhosts
```

### Expected Result

```
ignorerhosts yes
```

Run the following command and verify the output:

```bash
grep -Ei '^\s*ignorerhosts\s+no\b' /etc/ssh/sshd_config
```

Nothing should be returned.

## Remediation

### Command Line

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

```
IgnoreRhosts yes
```

## Default Value

IgnoreRhosts yes

## References

1. SSHD_CONFIG(5)

## CIS Controls

Version 7

9.2 Ensure Only Approved Ports, Protocols and Services Are Running - Ensure that only network ports, protocols, and services listening on a system with validated business needs, are running on each system.

## Profile Applicability

- Level 1 - Server
- Level 1 - Workstation

## Assessment Status

Automated