Ensure the --client-ca-file argument for API Servers is set appropriately

Error: The --client-ca-file argument for API Servers is not set appropriately

Bridgecrew Policy ID: BC_K8S_97
Checkov Check ID: CKV_K8S_140
Severity: LOW

The --client-ca-file argument for API Servers is not set appropriately

Description

Enable Kubelet authentication using certificates. The connections from the apiserver to the kubelet are used for fetching logs for pods, attaching (through kubectl) to running pods, and using the kubelet’s port-forwarding functionality. These connections terminate at the kubelet’s HTTPS endpoint. By default, the apiserver does not verify the kubelet’s 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.

Fix - Buildtime

Kubernetes

  • Kind: Pod
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    component: kubelet
    tier: control-plane
  name: kubelet
  namespace: kube-system
spec:
  containers:
  - command:
+   - kubelet
+   - --root-ca-file=test.pem
    image: gcr.io/google_containers/kubelet-amd64:v1.6.0
    ...

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