Ensure that the --service-account-key-file argument is set as appropriate (API Server)

Explicitly set a service account public key file for service accounts on the apiserver. By default, if no --service-account-key-file is specified to the apiserver, it uses the private key from the TLS serving certificate to verify service account tokens. To ensure that the keys for service account tokens could be rotated as needed, a separate public/private key pair should be used for signing service account tokens. Hence, the public key should be specified to the apiserver with --service-account-key-file.

Risk Level: Low
Cloud Entity: Pods
CloudGuard Rule ID: D9.K8S.OPE.03
Covered by Spectral: Yes
Category: Compute

GSL LOGIC

KubernetesPod where labels contain [value='kube-apiserver'] and namespace = 'kube-system' should have spec.containers with [parsedArgs contain [key like 'service-account-key-file' ]]

REMEDIATION

Edit the API server pod specification file $apiserverconf
on the master node and set the --service-account-key-file parameter
to the public key file for service accounts:
--service-account-key-file=<filename>

References

  1. https://kubernetes.io/docs/admin/kube-apiserver/
  2. https://github.com/kubernetes/kubernetes/issues/24167

Pods

Pods are the smallest deployable units of computing that can be created and managed in Kubernetes.A Pod is a group of one or more containers (such as Docker containers), with shared storage/network, and a specification for how to run the containers.

Compliance Frameworks

  • CIS Kubernetes Benchmark v1.20
  • CIS Kubernetes Benchmark v1.23
  • CIS Kubernetes Benchmark v1.24
  • CIS Kubernetes Benchmark v1.4.0
  • CIS Kubernetes Benchmark v1.5.1
  • CIS Kubernetes Benchmark v1.6.1
  • Kubernetes NIST.SP.800-190
  • Kubernetes v.1.13 CloudGuard Best Practices
  • Kubernetes v.1.14 CloudGuard Best Practices