CIS-1.2.28 - Ensure that the API Server --etcd-cafile argument is set as appropriate

Ensure that the API Server --etcd-cafile argument is set as appropriate

Framework

CIS

Severity

High

Description of the the issue

etcd is a highly-available key value store used by Kubernetes deployments for persistent storage of all of its REST API objects. These objects are sensitive in nature and should be protected by client authentication. This requires the API server to identify itself to the etcd server using a SSL Certificate Authority file.

Related resources

Pod

What does this control test

etcd should be configured to make use of TLS encryption for client connections.

How to check it manually

Run the following command on the Control Plane node:

ps -ef | grep kube-apiserver

Verify that the --etcd-cafile argument exists and it is set as appropriate.

Remediation

Follow the Kubernetes documentation and set up the TLS connection between the apiserver and etcd. Then, edit the API server pod specification file /etc/kubernetes/manifests/kube-apiserver.yaml on the master node and set the etcd certificate authority file parameter.

--etcd-cafile=<path/to/ca-file>

Impact Statement

TLS and client certificate authentication must be configured for etcd.

Default Value

By default, --etcd-cafile is not set.

Example

No example