1.1.7.1 Ensure separate partition exists for /home

Information

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

Rationale:

The reasoning for mounting /home on a separate partition is as follow.

Protection from resource exhaustion

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.

Fine grained control over the mount

Configuring /home as its own file system allows an administrator to set additional mount options such as noexec/nosuid/nodev. These options limits an attackers 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.

Protection of user data

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.

Solution

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.

See Also

https://workbench.cisecurity.org/files/3939

Item Details

Category: ACCESS CONTROL, MEDIA PROTECTION

References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|MP-2, CSCv7|14.6

Plugin: Unix

Control ID: 8808ccee62900ad4ed5692b060c1ef2b7d50fb84f0a693117f7170cc4d2e8e84