CIS-5.2.12 - Minimize the admission of HostPath volumes

Minimize the admission of HostPath volumes

Framework

CIS

Severity

Medium

Description of the the issue

A container which mounts a hostPath volume as part of its specification will have access to the filesystem of the underlying cluster node. The use of hostPath volumes may allow containers access to privileged areas of the node filesystem.

There should be at least one admission control policy defined which does not permit containers to mount hostPath volumes.

If you need to run containers which require hostPath volumes, this should be defined in a separate policy and you should carefully check to ensure that only limited service accounts and users are given permission to use that policy.

Related resources

MutatingWebhookConfiguration, Namespace, ValidatingWebhookConfiguration

What does this control test

Do not generally admit containers which make use of hostPath volumes.

How to check it manually

List the policies in use for each namespace in the cluster, ensure that each policy disallows the admission of containers with hostPath volumes.

Remediation

Add policies to each namespace in the cluster which has user workloads to restrict the admission of containers which use hostPath volumes.

Impact Statement

Pods defined which make use of hostPath volumes will not be permitted unless they are run under a spefific policy.

Default Value

By default, there are no restrictions on the creation of hostPath volumes.

Example

No example