# Cis Ubuntu1204 V110 7 2 6

> Enable Bad Error Message Protection

- Skill: `cyberstrikeus/cis-ubuntu1204-v110-7-2-6` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1204-v110-7-2-6`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1204-v110-7-2-6/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-ubuntu1204-v110-7-2-6

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# 7.2.6 Enable Bad Error Message Protection (Scored)

## Profile Applicability

- Level 1

## Description

Setting `icmp_ignore_bogus_error_responses` to 1 prevents the kernel from logging bogus responses (RFC-1122 non-compliant) from broadcast reframes, keeping file systems from filling up with useless log messages.

## Rationale

Some routers (and some attackers) will send responses that violate RFC-1122 and attempt to fill up a log file system with many useless error messages.

## Audit Procedure

### Using Command Line

Perform the following to determine if bogus messages will be ignored.

```bash
/sbin/sysctl net.ipv4.icmp_ignore_bogus_error_responses
```

## Expected Result

```
net.ipv4.icmp_ignore_bogus_error_responses = 1
```

## Remediation

### Using Command Line

Set the `net.ipv4.icmp_ignore_bogus_error_responses` parameter to 1 in `/etc/sysctl.conf`:

```bash
net.ipv4.icmp_ignore_bogus_error_responses=1
```

Modify active kernel parameters to match:

```bash
/sbin/sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
/sbin/sysctl -w net.ipv4.route.flush=1
```

## Default Value

Bogus error message protection is disabled by default.

## References

- CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0

## Profile

Level 1 - Scored