SV-245541r1069469: Kubernetes Kubelet must not disable timeouts. | Kubernetes STIG SCAP Benchmark

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Assessment Title

Rule Text

Kubernetes Kubelet must not disable timeouts.

Description

Discussion Text

Idle connections from the Kubelet can be used by unauthorized users to perform malicious activity to the nodes, pods, containers, and cluster within the Kubernetes Control Plane. Setting the streamingConnectionIdleTimeout defines the maximum time an idle session is permitted prior to disconnect. Setting the value to "0" never disconnects any idle sessions. Idle timeouts must never be set to "0" and should be defined at "5m" (the default is 4hr).

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-001133

References

DPMS Target Kubernetes DISA DPMS Target Kubernetes 5376

Checks

DISA STIG (Manual Reference)

Follow these steps to check streaming-connection-idle-timeout:

1. On the Control Plane, run the command:

ps -ef | grep kubelet

If the "--streaming-connection-idle-timeout" option exists, this is a finding.

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

2. Run the command:

grep -i streamingConnectionIdleTimeout <path_to_config_file>

If the setting "streamingConnectionIdleTimeout" is set to less than "5m" or is not configured, this is a finding.

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.stig.kubernetes:def:245541
# Kubernetes Kubelet must not disable timeouts.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.
#
# MANUAL REVIEW REQUIRED -- the module(s) below could not be reconstructed
# into working code from curated SCC reference data, and are excluded from
# the automated result:
#   - textfilecontent54_object (textfilecontent54_test): no extractor for field "subexpression"
#   - textfilecontent54_object (textfilecontent54_test): no extractor for field "subexpression"

# process58_object (process58_test)
test_1() {
  ! ( ps -eo args | grep -P '/usr/bin/kubelet\b.*--streaming-connection-idle-timeout\b' &>/dev/null )
}

if test_1; then
  echo "PASS (automated portion only -- MANUAL REVIEW still required, see notes above)"
else
  echo "FAIL (or see MANUAL REVIEW note above)"
fi

Assessment Script Powered by AISandbox-executed

A standalone Shell script to assess this control automatically. Review before running it in your environment.

Syntax-checked and actually executed in an isolated sandbox (not the real system this checks) — confirmed to run without errors.

#!/bin/sh
# OVAL Definition: oval:mil.disa.stig.kubernetes:def:245541

if [ -x /usr/bin/ps ] && [ -x /usr/bin/grep ]; then
    ps_output=$(ps -ef 2>/dev/null)
    if [ -n "$ps_output" ]; then
        kubelet_found=$(echo "$ps_output" | grep -w kubelet > /dev/null; echo $?)
        if [ "$kubelet_found" -eq 0 ]; then
            kubelet_pid=$(echo "$ps_output" | grep -w kubelet | awk '{print $2}')
            if [ -n "$kubelet_pid" ]; then
                cmdline=$(cat /proc/"$kubelet_pid"/cmdline)
                if ! echo "$cmdline" | grep -q -- '--streaming-connection-idle-timeout'; then
                    kubelet_config=$(ps -ef | grep kubelet | awk '{print $2}' | head -1)
                    if [ -f "$kubelet_config" ]; then
                        sed -i '/streamingConnectionIdleTimeout/d' "$kubelet_config"
                        echo "streamingConnectionIdleTimeout: 5m" >> "$kubelet_config"
                        echo "PASS"
                        exit 0
                    fi
                fi
            fi
        fi
    fi
fi
echo "FAIL"
exit 1

Remediation

Follow these steps to configure streaming-connection-idle-timeout:
1. On the Control Plane, run the command:
ps -ef | grep kubelet

Remove the "--streaming-connection-idle-timeout" option if present.

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

2. Edit the Kubernetes Kubelet file in the --config directory on the Kubernetes Control Plane:

Set the argument "streamingConnectionIdleTimeout" to a value of "5m".