5.1.11 Minimize access to the approval sub-resource of certificatesigningrequests objects

Information

Users with access to the update the approval sub-resource of CertificateSigningRequests objects can approve new client certificates for the Kubernetes API effectively allowing them to create new high-privileged user accounts.

This can allow for privilege escalation to full cluster administrator, depending on users configured in the cluster

The ability to update certificate signing requests should be limited.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

Where possible, remove access to the approval sub-resource of CertificateSigningRequests objects.

See Also

https://workbench.cisecurity.org/benchmarks/22107