C-0204 - Minimize the admission of containers which use HostPorts
Framework
cis-v1.23-t1.0.1
Severity
Medium
Description of the the issue
Host ports connect containers directly to the host's network. This can bypass controls such as network policy.
There should be at least one admission control policy defined which does not permit containers which require the use of HostPorts.
If you need to run containers which require HostPorts, 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 which require the use of HostPorts.
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 which have hostPort
sections.
Remediation
Add policies to each namespace in the cluster which has user workloads to restrict the admission of containers which use hostPort
sections.
Impact Statement
Pods defined with hostPort
settings in either the container, initContainer or ephemeralContainer sections will not be permitted unless they are run under a specific policy.
Default Value
By default, there are no restrictions on the use of HostPorts.
Example
No example
Updated 3 months ago