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V-242387

CAT I (High)

The Kubernetes Kubelet must have the "readOnlyPort" flag disabled.

Rule ID

SV-242387r1137639_rule

STIG

Kubernetes Security Technical Implementation Guide

Version

V2R6

CCIs

CCI-000213

Discussion

Kubelet serves a small REST API with read access to port 10255. The read-only port for Kubernetes provides no authentication or authorization security control. Providing unrestricted access on port 10255 exposes Kubernetes pods and containers to malicious attacks or compromise. Port 10255 is deprecated and should be disabled.

Check Content

On each Control Plane and Worker Node, run the command:
ps -ef | grep kubelet

If the "--read-only-port" option exists, this is a finding. 

Note the path to the config file (identified by --config).

Run the command:
grep -i readOnlyPort <path_to_config_file>

If the setting "readOnlyPort" exists and is not set to "0", this is a finding.

Fix Text

On each Control Plane and Worker Node, run the command:
ps -ef | grep kubelet

Remove the "--read-only-port" option if present.

Note the path to the config file (identified by --config).

Edit the config file: 
Set "readOnlyPort" to "0" or remove the setting.

Restart the kubelet service using the following command:
systemctl daemon-reload && systemctl restart kubelet