cis-gcp-cos-4-1-2-1

name	cis-gcp-cos-4.1.2.1
description	Ensure journald is configured to compress large log files
category	cis-gcp-cos
version	1.2.0
author	cyberstrike-official
tags	["cis","gcp","container-optimized-os","logging","journald","log-files"]
cis_id	4.1.2.1
cis_benchmark	CIS Google Container-Optimized OS Benchmark v1.2.0
tech_stack	["gcp","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

4.1.2.1 Ensure journald is configured to compress large log files (Automated)

Description

The journald system includes the capability of compressing overly large files to avoid filling up the system with logs or making the logs unmanageably large.

Rationale

Uncompressed large files may unexpectedly fill a filesystem leading to resource unavailability. Compressing logs prior to write can prevent sudden, unexpected filesystem impacts.

Audit Procedure

Review /etc/systemd/journald.conf and verify that large files will be compressed:

# grep -e Compress /etc/systemd/journald.conf
# Compress=yes

Expected Result

The output should show Compress=yes.

Remediation

Edit the /etc/systemd/journald.conf file and add the following line:

Compress=yes

Reload the configuration to be effective.

# systemctl force-reload systemd-journald

/etc is stateless on Container-Optimized OS. Therefore, /etc cannot be used to make these changes persistent across reboots. The steps mentioned above needs to be performed after every boot.

Default Value

The main configuration file /etc/systemd/journald.conf is read before any of the custom *.conf files. If there are custom configs present, they override the main configuration parameters.

References

1. https://github.com/konstruktoid/hardening/blob/master/systemd.adoc#etcsystemdjournaldconf

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	8.3 Ensure Adequate Audit Log Storage - Ensure that logging destinations maintain adequate storage to comply with the enterprise's audit log management process.	x	x	x
v7	6.4 Ensure adequate storage for logs - Ensure that all systems that store logs have adequate storage space for the logs generated.		x	x