turbot/steampipe-mod-kubernetes-compliance

Control: 5.2.4 Minimize the admission of containers wishing to share the host network namespace

Description

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

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.

Remediation

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

References

  1. https://kubernetes.io/docs/concepts/policy/pod-security-policy/

Usage

Run the control in your terminal:

powerpipe control run kubernetes_compliance.control.cis_kube_v120_v100_5_2_4

Snapshot and share results via Turbot Pipes:

powerpipe login
powerpipe control run kubernetes_compliance.control.cis_kube_v120_v100_5_2_4 --share

SQL

This control uses a named query:

select
coalesce(uid, concat(path, ':', start_line)) as resource,
case
when host_network then 'alarm'
else 'ok'
end as status,
case
when host_network then 'Pod security policy ' || name || ' pods can use the host network.'
else 'Pod security policy ' || name || ' pods cannot use the host network.'
end as reason
, coalesce(context_name, '') as context_name, source_type, coalesce(path || ':' || start_line || '-' || end_line, '') as path
from
kubernetes_pod_security_policy;

Tags