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.

```bash
# 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

When modifying `/home` it is advisable to bring the system to emergency mode (so auditd is not running), rename the existing directory, mount the new file system, and migrate the data over before returning to multi-user mode.

## References

1. AJ Lewis, "LVM HOWTO", http://tldp.org/HOWTO/LVM-HOWTO/
2. NIST SP 800-53 Rev. 5: CM-7

## CIS Controls

v8 - 3.3 Configure Data Access Control Lists (IG 1, IG 2, IG 3)
v7 - 14.6 Protect Information through Access Control Lists (IG 1, IG 2, IG 3)

MITRE ATT&CK Mappings: T1499, T1499.001 | TA0005 | M1038