CIS-5.2.2 - Minimize the admission of privileged containers

Minimize the admission of privileged containers

Framework

CIS

Severity

High

Description of the the issue

Privileged containers have access to all Linux Kernel capabilities and devices. A container running with full privileges can do almost everything that the host can do. This flag exists to allow special use-cases, like manipulating the network stack and accessing devices.

There should be at least one admission control policy defined which does not permit privileged containers.

If you need to run privileged containers, 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 permit containers to be run with the securityContext.privileged flag set to true.

How to check it manually

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

Remediation

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

Impact Statement

Pods defined with spec.containers[].securityContext.privileged: true, spec.initContainers[].securityContext.privileged: true and spec.ephemeralContainers[].securityContext.privileged: true will not be permitted.

Default Value

By default, there are no restrictions on the creation of privileged containers.

Example

No example