cis-k8s-v1120-5-2-10

name	cis-k8s-v1120-5.2.10
description	Minimize the admission of Windows HostProcess Containers (Manual)
category	cis-k8s
version	1.12.0
author	cyberstrike-official
tags	["cis","kubernetes","policies","pod-security"]
cis_id	5.2.10
cis_benchmark	CIS Kubernetes Benchmark v1.12.0
tech_stack	["kubernetes"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

5.2.10 Minimize the admission of Windows HostProcess Containers (Manual)

Profile Applicability

• Level 1 - Master Node

Description

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

Rationale

A Windows container making use of the hostProcess flag can interact with the underlying Windows cluster node. As per the Kubernetes documentation, this provides "privileged access" to the Windows node.

Where Windows containers are used inside a Kubernetes cluster, there should be at least one admission control policy which does not permit hostProcess Windows containers.

If you need to run Windows containers which require hostProcess, 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.

Impact

Pods defined with securityContext.windowsOptions.hostProcess: true will not be permitted unless they are run under a specific policy.

Audit Procedure

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

Remediation

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

Default Value

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

References

1. https://kubernetes.io/docs/tasks/configure-pod-container/create-hostprocess-pod/
2. https://kubernetes.io/docs/concepts/security/pod-security-standards/

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	16.11 Leverage Vetted Modules or Services for Application Security Components		X	X
v7	4.7 Limit Access to Script Tools		X	X
v7	14.6 Protect Information through Access Control Lists	X	X