--kubelet-client-certificate and --kubelet-client-key arguments are set as appropriate
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--kubelet-client-certificate and --kubelet-client-key arguments are set as appropriate

kubernetes

Classification:

compliance

Framework:

cis-kubernetes

Control:

1.2.5

Set up the kubernetes integration.

Overview

Description

Enable certificate based kubelet authentication.

Rationale

The apiserver, by default, does not authenticate itself to the kubelet’s HTTPS endpoints. The requests from the apiserver are treated anonymously. You should set up certificate-based kubelet authentication to ensure that the apiserver authenticates itself to kubelets when submitting requests.

Audit

Run the following command on the master node:

ps -ef | grep kube-apiserver

Verify that the --kubelet-client-certificate and --kubelet-client-key arguments exist and they are set as appropriate.

Remediation

Follow the Kubernetes documentation and set up the TLS connection between the apiserver and kubelets. Then, edit API server pod specification file /etc/kubernetes/manifests/kube-apiserver.yaml on the master node and set the kubelet client certificate and key parameters as below.

--kubelet-client-certificate=<path/to/client-certificate-file> 
--kubelet-client-key=<path/to/client-key-file>

Impact

You require TLS to be configured on apiserver as well as kubelets.

Default Value

By default, certificate-based kubelet authentication is not set.

References

  1. https://kubernetes.io/docs/admin/kube-apiserver/
  2. https://kubernetes.io/docs/admin/kubelet-authentication-authorization/
  3. https://kubernetes.io/docs/concepts/cluster-administration/master-node-communication/#apiserver—kubelet

CIS Controls

Version 6.3.4 Use Only Secure Channels For Remote System Administration - Perform all remote administration of servers, workstation, network devices, and similar equipment over secure channels. Protocols such as telnet, VNC, RDP, or others that do not actively support strong encryption should only be used if they are performed over a secondary encryption channel, such as SSL, TLS or IPSEC.

Version 7.4.5 Use Multifactor Authentication For All Administrative Access - Use multi-factor authentication and encrypted channels for all administrative account access.