cis-ubuntu1804-v220-5-1-2-7

name	cis-ubuntu1804-v220-5-1-2-7
description	Ensure rsyslog is not configured to receive logs from a remote client
category	cis-logging
version	2.2.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-18.04","rsyslog","logging"]
cis_id	5.1.2.7
cis_benchmark	CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

5.1.2.7 Ensure rsyslog is not configured to receive logs from a remote client (Automated)

Profile

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

Description

RSyslog supports the ability to receive messages from remote hosts, thus acting as a log server. Clients should not receive data from other hosts.

Rationale

If a client is configured to also receive data, thus turning it into a server, the client system is acting outside it's operational boundary.

Audit Procedure

Command Line

Review the /etc/rsyslog.conf and /etc/rsyslog.d/*.conf files and verify that the system is not configured to accept incoming logs.

Old format:

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

No output expected.

New format:

grep -P -- '^\h*module\(load="imtcp"\)' /etc/rsyslog.conf /etc/rsyslog.d/*.conf
grep -P -- '^\h*input\(type="imtcp" port="514"\)' /etc/rsyslog.conf /etc/rsyslog.d/*.conf

No output expected.

Expected Result

No output should be returned for any of the commands.

Remediation

Command Line

Remove or comment out any lines in /etc/rsyslog.conf and /etc/rsyslog.d/*.conf that configure rsyslog to accept incoming logs. Restart the service:

systemctl restart rsyslog

Default Value

rsyslog is not configured to receive logs from remote clients by default.

References

1. NIST SP 800-53 Rev. 5: AU-2, AU-12, CM-6, CM-7

CIS Controls

Controls Version	Control
v8	4.8 Uninstall or Disable Unnecessary Services on Enterprise Assets and Software - Uninstall or disable unnecessary services on enterprise assets and software.
v8	8.2 Collect Audit Logs - Collect audit logs. Ensure that logging, per the enterprise's audit log management process, has been enabled across enterprise assets.