Details

The Kubernetes API Server controls Kubernetes via an API interface. A user who has access to the API essentially has root access to the entire Kubernetes cluster. To control access, users must be authenticated and authorized. By allowing anonymous connections, the controls put in place to secure the API can be bypassed.

Setting anonymous authentication to ‘false’ also disables unauthenticated requests from kubelets.

While there are instances where anonymous connections may be needed (e.g., health checks) and Role-Based Access Controls (RBAC) are in place to limit the anonymous access, this access should be disabled, and only enabled when necessary.

Solution

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Master Node. Set the argument –anonymous-auth to ‘false’.

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Kubernetes_V1R4_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Access Control.This control applies to the following type of system Unix.

References

• 800-53|AC-3
• CAT|I
• CCI|CCI-000213
• Rule-ID|SV-242390r712526_rule
• STIG-ID|CNTR-K8-000360
• Vuln-ID|V-242390

Source

• Tenable.com/audits