API server should only authorize explicitly authorized requests

kubernetes

Classification:

compliance

Framework:

cis-kubernetes

Control:

1.2.7

Set up the kubernetes integration.

Description

Do not always authorize all requests.

Rationale

The API Server, can be configured to allow all requests. This mode should not be used on any production cluster.

Audit

Run the following command on the master node:

ps -ef | grep kube-apiserver

Verify that the --authorization-mode argument exists and is not set to AlwaysAllow.

Remediation

Edit the API server pod specification file /etc/kubernetes/manifests/kube-apiserver.yaml on the master node and set the --authorization-mode parameter to values other than AlwaysAllow. One such example could be as below:

--authorization-mode=RBAC

Impact

Only authorized requests will be served.

Default value

By default, AlwaysAllow is not enabled.

References

  1. https://kubernetes.io/docs/admin/kube-apiserver/
  2. https://kubernetes.io/docs/admin/authorization/node/

CIS controls

Version 6.9.1 Limit Open Ports, Protocols, and Services - Ensure that only ports, protocols, and services with validated business needs are running on each system.

Version 7.9.2 Ensure Only Approved Ports, Protocols and Services Are Running - Ensure that only network ports, protocols, and services listening on a system with validated business needs, are running on each system.