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 certificateaigningrequest 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

Rationale:

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 certificatesigningrequest objects.

See Also

https://workbench.cisecurity.org/benchmarks/12958