cis-ubuntu2004-v300-1-1-2-3-1

name	cis-ubuntu2004-v300-1-1-2-3-1
description	Ensure separate partition exists for /home
category	cis-storage
version	3.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-20.04","partition"]
cis_id	1.1.2.3.1
cis_benchmark	CIS Ubuntu Linux 20.04 LTS Benchmark v3.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

Ensure separate partition exists for /home

Profile

Level 2 - Server, Level 2 - Workstation, Assessment: Automated

Description

The /home directory is used to support disk storage needs of local users.

Rationale

The default installation only creates a single / partition. Since the /home directory contains user generated data, there is a risk of resource exhaustion. It will essentially have the whole disk available to fill up and impact the system as a whole. In addition, other operations on the system could fill up the disk unrelated to /home and impact all local users.

Configuring /home as its own file system allows an administrator to set additional mount options such as noexec/nosuid/nodev. These options limit an attacker's ability to create exploits on the system. In the case of /home options such as usrquota/grpquota may be considered to limit the impact that users can have on each other with regards to disk resource exhaustion. Other options allow for specific behavior. See man mount for exact details regarding filesystem-independent and filesystem-specific options.

As /home contains user data, care should be taken to ensure the security and integrity of the data and mount point.

Impact

Resizing filesystems is a common activity in cloud-hosted servers. Separate filesystem partitions may prevent successful resizing or may require the installation of additional tools solely for the purpose of resizing operations. The use of these additional tools may introduce their own security considerations.

Audit Procedure

Command Line

Run the following command and verify output shows /home is mounted.

# findmnt -kn /home

Example output:

/home   /dev/sdb  ext4   rw,nosuid,nodev,relatime,seclabel

Expected Result

/home should be mounted as a separate partition.

Remediation

Command Line

For new installations, during installation create a custom partition setup and specify a separate partition for /home. For systems that were previously installed, create a new partition and configure /etc/fstab as appropriate.

Default Value

Not configured by default.

Additional Information