cis-ubuntu1604-v200-4-2-1-6

name	cis-ubuntu1604-v200-4-2-1-6
description	Ensure remote rsyslog messages are only accepted on designated log hosts
category	cis-logging
version	2.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-16.04","logging","rsyslog"]
cis_id	4.2.1.6
cis_benchmark	CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Control 4.2.1.6

Profile

• Level: 1 - Server
• Level: 1 - Workstation
• Assessment Status: Manual

Description

By default, rsyslog does not listen for log messages coming in from remote systems. The ModLoad tells rsyslog to load the imtcp.so module so it can listen over a network via TCP. The InputTCPServerRun option instructs rsyslogd to listen on the specified TCP port.

Rationale

The guidance in the section ensures that remote log hosts are configured to only accept rsyslog data from hosts within the specified domain and that those systems that are not designed to be log hosts do not accept any remote rsyslog messages. This provides protection from spoofed log data and ensures that system administrators are reviewing reasonably complete syslog data in a central location.

Note: The $ModLoad imtcp line can have the .so extension added to the end of the module, or use the full path to the module.

Impact

None.

Audit Procedure

Run the following commands and verify the resulting lines are:

• Not commented on designated log hosts
• Commented or not present on all others

Command Line

Run the following command and verify the output for $ModLoad imtcp:

grep '$ModLoad imtcp' /etc/rsyslog.conf /etc/rsyslog.d/*.conf

Output for designated log hosts:

$ModLoad imtcp

Output for systems that are not log hosts: (No output is also acceptable)

# $ModLoad imtcp

Run the following command and verify the output for $InputTCPServerRun:

grep '$InputTCPServerRun' /etc/rsyslog.conf /etc/rsyslog.d/*.conf

Output for designated log hosts:

$InputTCPServerRun 514

Output for systems that are not log hosts: (No output is also acceptable)

# $InputTCPServerRun 514