# CIS Ubuntu 14.04 LTS - 4.1.6 Ensure events that modify the system's network environment are collected

> Collect audit events for changes to network environment files and system calls

- Skill: `cyberstrikeus/cis-ubuntu-14-04-lts-4-1-6-ensure-events-that-modify-the-sys` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu-14-04-lts-4-1-6-ensure-events-that-modify-the-sys`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu-14-04-lts-4-1-6-ensure-events-that-modify-the-sys/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-ubuntu-14-04-lts-4-1-6-ensure-events-that-modify-the-sys

---


# 4.1.6 Ensure events that modify the system's network environment are collected (Scored)

## Profile Applicability

- Level 2 - Server
- Level 2 - Workstation

## Description

Record changes to network environment files or system calls. The below parameters monitor the `sethostname` (set the systems host name) or `setdomainname` (set the systems domainname) system calls, and write an audit event on system call exit. The other parameters monitor the `/etc/issue` and `/etc/issue.net` files (messages displayed pre-login), `/etc/hosts` (file containing host names and associated IP addresses) and `/etc/sysconfig/network` (directory containing network interface scripts and configurations) files.

## Rationale

Monitoring `sethostname` and `setdomainname` will identify potential unauthorized changes to host and domainname of a system. The changing of these names could potentially break security parameters that are set based on those names. The `/etc/hosts` file is monitored for changes in the file that can indicate an unauthorized intruder is trying to change machine associations with IP addresses and trick users and processes into connecting to unintended machines. Monitoring `/etc/issue` and `/etc/issue.net` is important, as intruders could put disinformation into those files and trick users into providing information to the intruder. Monitoring `/etc/sysconfig/network` is important as it can show if network interfaces or scripts are being modified in a way that can lead to the machine becoming unavailable or compromised. All audit records will be tagged with the identifier "system-locale."

## Audit Procedure

On a 32 bit system run the following commands:

```bash
grep system-locale /etc/audit/audit.rules
auditctl -l | grep system-locale
```

Verify output of both matches:

```
-a always,exit -F arch=b32 -S sethostname -S setdomainname -k system-locale
-w /etc/issue -p wa -k system-locale
-w /etc/issue.net -p wa -k system-locale
-w /etc/hosts -p wa -k system-locale
-w /etc/sysconfig/network -p wa -k system-locale
```

On a 64 bit system run the following commands:

```bash
grep system-locale /etc/audit/audit.rules
auditctl -l | grep system-locale
```

Verify output of both matches:

```
-a always,exit -F arch=b64 -S sethostname -S setdomainname -k system-locale
-a always,exit -F arch=b32 -S sethostname -S setdomainname -k system-locale
-w /etc/issue -p wa -k system-locale
-w /etc/issue.net -p wa -k system-locale
-w /etc/hosts -p wa -k system-locale
-w /etc/sysconfig/network -p wa -k system-locale
```

## Expected Result

The audit rules for system-locale should be present and active.

## Remediation

For 32 bit systems add the following lines to the `/etc/audit/audit.rules` file:

```bash
-a always,exit -F arch=b32 -S sethostname -S setdomainname -k system-locale
-w /etc/issue -p wa -k system-locale
-w /etc/issue.net -p wa -k system-locale
-w /etc/hosts -p wa -k system-locale
-w /etc/sysconfig/network -p wa -k system-locale
```

For 64 bit systems add the following lines to the `/etc/audit/audit.rules` file:

```bash
-a always,exit -F arch=b64 -S sethostname -S setdomainname -k system-locale
-a always,exit -F arch=b32 -S sethostname -S setdomainname -k system-locale
-w /etc/issue -p wa -k system-locale
-w /etc/issue.net -p wa -k system-locale
-w /etc/hosts -p wa -k system-locale
-w /etc/sysconfig/network -p wa -k system-locale
```

**Notes:** `/etc/sysconfig/network` is common to Red Hat and SUSE based distributions. You should expand or replace this coverage to any network configuration files on your system such as `/etc/network` on Debian based distributions.

Reloading the auditd config to set active settings may require a system reboot.

## Default Value

Not configured by default.

## References

1. CIS Controls v6.1 - 3.6 Implement Automated Configuration Monitoring System

## Profile

- Level 2 - Server
- Level 2 - Workstation