cis-k8s-v1110-4-2-5

name	cis-k8s-v1110-4.2.5
description	Ensure that the --streaming-connection-idle-timeout argument is not set to 0 (Manual)
category	cis-k8s
version	1.11.0
author	cyberstrike-official
tags	["cis","kubernetes","worker-node","kubelet","streaming-connection-idle-timeout","dos-prevention"]
cis_id	4.2.5
cis_benchmark	CIS Kubernetes Benchmark v1.11.0
tech_stack	["kubernetes"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

4.2.5 Ensure that the --streaming-connection-idle-timeout argument is not set to 0 (Manual)

Profile Applicability

• Level 1 - Worker Node

Description

Do not disable timeouts on streaming connections.

Rationale

Setting idle timeouts ensures that you are protected against Denial-of-Service attacks, inactive connections and running out of ephemeral ports.

Note: By default, --streaming-connection-idle-timeout is set to 4 hours which might be too high for your environment. Setting this as appropriate would additionally ensure that such streaming connections are timed out after serving legitimate use cases.

Impact

Long-lived connections could be interrupted.

Audit

Run the following command on each node:

ps -ef | grep kubelet

Verify that the --streaming-connection-idle-timeout argument is not set to 0. If the argument is not present, and there is a Kubelet config file specified by --config, check that it does not set streamingConnectionIdleTimeout to 0.

Remediation

If using a Kubelet config file, edit the file to set streamingConnectionIdleTimeout to a value other than 0. If using command line arguments, edit the kubelet service file /etc/kubernetes/kubelet.conf on each worker node and set the below parameter in KUBELET_SYSTEM_PODS_ARGS variable.

--streaming-connection-idle-timeout=5m

Based on your system, restart the kubelet service. For example:

systemctl daemon-reload
systemctl restart kubelet.service

Default Value

By default, --streaming-connection-idle-timeout is set to 4 hours.

References

1. https://kubernetes.io/docs/admin/kubelet/
2. https://github.com/kubernetes/kubernetes/pull/18552

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	10.5 Enable Anti-Exploitation Features		x	x