2.1.4 Ensure that the --client-ca-file argument is set as appropriate

Information

Enable Kubelet authentication using certificates.

Rationale:

The connections from the apiserver to the kubelet are used for fetching logs for pods, attaching (through kubectl) to running pods, and using the kubelets port-forwarding functionality. These connections terminate at the kubelets HTTPS endpoint. By default, the apiserver does not verify the kubelets serving certificate, which makes the connection subject to man-in-the-middle attacks, and unsafe to run over untrusted and/or public networks. Enabling Kubelet certificate authentication ensures that the apiserver could authenticate the Kubelet before submitting any requests.

Solution

Edit the kubelet service file '/etc/systemd/system/kubelet.service.d/10-kubeadm.conf' on each worker node and set the below parameter in 'KUBELET_AUTHZ_ARGS' variable.

--client-ca-file=

Based on your system, restart the 'kubelet' service. For example:

systemctl daemon-reload
systemctl restart kubelet.service

Impact:

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

See Also

https://workbench.cisecurity.org/files/2125

Item Details

Category: IDENTIFICATION AND AUTHENTICATION

References: 800-53|IA-5(2), CSCv6|14.2

Plugin: Unix

Control ID: 224b6e8fbf7484f99d59a426120515b76194e1346f2ed73cbd6b6ae6f7772c4d