Details

Limiting the number of attack vectors and implementing authentication and encryption on the endpoints available to external sources is paramount when securing the overall Kubernetes cluster. The Scheduler API service exposes port 10251/TCP by default for health and metrics information use. This port does not encrypt or authenticate connections. If this port is exposed externally, an attacker can use this port to attack the entire Kubernetes cluster. By setting the bind address to localhost (i.e., 127.0.0.1), only those internal services that require health and metrics information can access the Scheduler API.

Solution

Edit the Kubernetes Scheduler manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Master Node. Set the argument ‘–bind-address’ to ‘127.0.0.1’.

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|II
• CCI|CCI-000213
• Rule-ID|SV-242384r712508_rule
• STIG-ID|CNTR-K8-000300
• Vuln-ID|V-242384

Source

• Tenable.com/audits