cis-gke-v170-3-2-5

name	cis-gke-v170-3.2.5
description	Ensure that the --streaming-connection-idle-timeout argument is not set to 0 (Automated)
category	cis-gke
version	1.7.0
author	cyberstrike-official
tags	["cis","gke","kubernetes","gcp","kubelet","authentication","authorization","tls","event-capture","certificate-rotation"]
cis_id	3.2.5
cis_benchmark	CIS Google Kubernetes Engine (GKE) Benchmark v1.7.0
tech_stack	["kubernetes","gcp","gke"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

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

Profile Applicability

• Level 1

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

Audit Method 1:

First, SSH to the relevant node.

Run the following command on each node to find the running kubelet process:

ps -ef | grep kubelet

If the command line for the process includes the argument streaming-connection-idle-timeout verify that it is not set to 0.

If the streaming-connection-idle-timeout argument is not present in the output of the above command, refer instead to the config argument that specifies the location of the Kubelet config file e.g. --config /etc/kubernetes/kubelet-config.yaml.

Open the Kubelet config file:

cat /etc/kubernetes/kubelet-config.yaml

Verify that the streamingConnectionIdleTimeout argument is not set to 0.

Audit Method 2:

If using the api configz endpoint consider searching for the status of "streamingConnectionIdleTimeout":"4h0m0s" by extracting the live configuration from the nodes running kubelet.

Set the local proxy port and the following variables and provide proxy port number and node name;

HOSTNAME_PORT="localhost-and-port-number"
NODE_NAME="The-Name-Of-Node-To-Extract-Configuration" from the output of "kubectl get nodes"

kubectl proxy --port=8001 &

export HOSTNAME_PORT=localhost:8001 (example host and port number)
export NODE_NAME=gke-cluster-1-pool1-5e572947-r2hg (example node name from "kubectl get nodes")

curl -sSL "http:///api/v1/nodes//proxy/configz"