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Controller Manager Configuration File Ownership Is Root

More Info:​

Ensure that the controller-manager.conf file ownership is set to root:root.

Risk Level​

Low

Address​

Security

Compliance Standards​

  • CIS Kubernetes

Triage and Remediation​

Remediation​

Manual Steps

  1. On every control plane node, confirm the file exists and view current ownership:

    ls -l /etc/kubernetes/controller-manager.conf

  2. On every control plane node, change the file owner and group to root:root:

    sudo chown root:root /etc/kubernetes/controller-manager.conf

  3. (Optional) On every control plane node, lock down permissions if needed (common setting is 600):

    sudo chmod 600 /etc/kubernetes/controller-manager.conf

  4. On every control plane node, verify the ownership is now root:root:

    /bin/sh -c 'if test -e /etc/kubernetes/controller-manager.conf; then stat -c %U:%G /etc/kubernetes/controller-manager.conf; fi'
Using kubectl

kubectl cannot modify file ownership on control plane nodes, so it cannot be used to fix /etc/kubernetes/controller-manager.conf. This must be corrected directly on every control plane node’s host filesystem; see the Manual Steps section for the exact commands to run.

Automation
#!/usr/bin/env bash
#
# Fix ownership of /etc/kubernetes/controller-manager.conf to root:root
# Scope: run on every control plane node (with sudo/root privileges)
# Safe to re-run (idempotent).

set -euo pipefail

TARGET_FILE="/etc/kubernetes/controller-manager.conf"
DESIRED_OWNER="root"
DESIRED_GROUP="root"

echo "=== CIS 1.1.18: Ensure ${TARGET_FILE} ownership is ${DESIRED_OWNER}:${DESIRED_GROUP} ==="

if [ ! -e "${TARGET_FILE}" ]; then
  echo "INFO: ${TARGET_FILE} does not exist on this node. Nothing to change."
  exit 0
fi

current_owner="$(stat -c '%U' "${TARGET_FILE}")"
current_group="$(stat -c '%G' "${TARGET_FILE}")"

echo "Current ownership: ${current_owner}:${current_group}"

if [ "${current_owner}" = "${DESIRED_OWNER}" ] && [ "${current_group}" = "${DESIRED_GROUP}" ]; then
  echo "INFO: Ownership already set to ${DESIRED_OWNER}:${DESIRED_GROUP}. No change needed."
else
  echo "Updating ownership to ${DESIRED_OWNER}:${DESIRED_GROUP} ..."
  chown "${DESIRED_OWNER}:${DESIRED_GROUP}" "${TARGET_FILE}"
fi

echo "Verifying ownership..."
verified_owner_group="$(stat -c '%U:%G' "${TARGET_FILE}")"
echo "stat -c %U:%G ${TARGET_FILE} => ${verified_owner_group}"

if [ "${verified_owner_group}" != "${DESIRED_OWNER}:${DESIRED_GROUP}" ]; then
  echo "ERROR: Failed to set ownership on ${TARGET_FILE} to ${DESIRED_OWNER}:${DESIRED_GROUP}" >&2
  exit 1
fi

echo "SUCCESS: ${TARGET_FILE} ownership is correctly set to ${DESIRED_OWNER}:${DESIRED_GROUP}."

Usage:

  • Run this script on every control plane node as root, for example:
sudo bash ./fix-controller-manager-conf-ownership.sh

Additional Reading:​