C-0216 - Minimize the admission of containers wishing to share the host network namespace


cis-eks-t1.2.0, cis-aks-t1.2.0



Description of the the issue

A container running in the host's network namespace could access the local loopback device, and could access network traffic to and from other pods.

There should be at least one PodSecurityPolicy (PSP) defined which does not permit containers to share the host network namespace.

If you have need to run containers which require hostNetwork, this should be defined in a separate PSP and you should carefully check RBAC controls to ensure that only limited service accounts and users are given permission to access that PSP.

Related resources


What does this control test

Do not generally permit containers to be run with the hostNetwork flag set to true.

How to check it manually

Get the set of PSPs with the following command:

kubectl get psp

For each PSP, check whether privileged is enabled:

kubectl get psp <name> -o=jsonpath='{.spec.hostNetwork}'

Verify that there is at least one PSP which does not return true.


Create a PSP as described in the Kubernetes documentation, ensuring that the .spec.hostNetwork field is omitted or set to false.

Impact Statement

Pods defined with spec.hostNetwork: true will not be permitted unless they are run under a specific PSP.

Default Value

By default, PodSecurityPolicies are not defined.


No example