---
controls:
version: "gke-1.0"
id: 4
text: "Worker Node Security Configuration"
type: "node"
groups:
  - id: 4.1
    text: "Worker Node Configuration Files"
    checks:
      - id: 4.1.1
        text: "Ensure that the kubelet service file permissions are set to 644 or more restrictive (Not Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."
        scored: false

      - id: 4.1.2
        text: "Ensure that the kubelet service file ownership is set to root:root (Not Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."
        scored: false

      - id: 4.1.3
        text: "Ensure that the proxy kubeconfig file permissions are set to 644 or more restrictive (Scored)"
        audit: '/bin/sh -c ''if test -e $proxykubeconfig; then stat -c permissions=%a $proxykubeconfig; fi'' '
        tests:
          test_items:
            - flag: "permissions"
              compare:
                op: bitmask
                value: "644"
        remediation: |
          Run the below command (based on the file location on your system) on each worker node.
          For example,
          chmod 644 $proxykubeconfig
        scored: true

      - id: 4.1.4
        text: "Ensure that the proxy kubeconfig file ownership is set to root:root (Scored)"
        audit: '/bin/sh -c ''if test -e $proxykubeconfig; then stat -c %U:%G $proxykubeconfig; fi'' '
        tests:
          test_items:
            - flag: root:root
        remediation: |
          Run the below command (based on the file location on your system) on each worker node.
          For example, chown root:root $proxykubeconfig
        scored: true

      - id: 4.1.5
        text: "Ensure that the kubelet.conf file permissions are set to 644 or more restrictive (Not Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."
        scored: false

      - id: 4.1.6
        text: "Ensure that the kubelet.conf file ownership is set to root:root (Not Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."
        scored: false

      - id: 4.1.7
        text: "Ensure that the certificate authorities file permissions are set to 644 or more restrictive (Not Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."
        scored: false

      - id: 4.1.8
        text: "Ensure that the client certificate authorities file ownership is set to root:root (Not Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."
        scored: false

      - id: 4.1.9
        text: "Ensure that the kubelet configuration file has permissions set to 644 or more restrictive (Scored)"
        audit: '/bin/sh -c ''if test -e $kubeletconf; then stat -c permissions=%a $kubeletconf; fi'' '
        tests:
          test_items:
            - flag: "permissions"
              set: true
              compare:
                op: bitmask
                value: "644"
        remediation: |
          Run the following command (using the config file location identified in the Audit step)
          chmod 644 $kubeletconf
        scored: true

      - id: 4.1.10
        text: "Ensure that the kubelet configuration file ownership is set to root:root (Scored)"
        audit: '/bin/sh -c ''if test -e $kubeletconf; then stat -c %U:%G $kubeletconf; fi'' '
        tests:
          test_items:
            - flag: root:root
        remediation: |
          Run the following command (using the config file location identified in the Audit step)
          chown root:root $kubeletconf
        scored: true

  - id: 4.2
    text: "Kubelet"
    checks:
      - id: 4.2.1
        text: "Ensure that the --anonymous-auth argument is set to false (Scored)"
        audit: "/bin/ps -fC $kubeletbin"
        audit_config: "/bin/cat $kubeletconf"
        tests:
          test_items:
            - flag: "--anonymous-auth"
              path: '{.authentication.anonymous.enabled}'
              compare:
                op: eq
                value: false
        remediation: |
          If using a Kubelet config file, edit the file to set authentication: anonymous: enabled to
          false.
          If using executable arguments, edit the kubelet service file
          $kubeletsvc on each worker node and
          set the below parameter in KUBELET_SYSTEM_PODS_ARGS variable.
          --anonymous-auth=false
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: true

      - id: 4.2.2
        text: "Ensure that the --authorization-mode argument is not set to AlwaysAllow (Scored)"
        audit: "/bin/ps -fC $kubeletbin"
        audit_config: "/bin/cat $kubeletconf"
        tests:
          test_items:
            - flag: --authorization-mode
              path: '{.authorization.mode}'
              compare:
                op: nothave
                value: AlwaysAllow
        remediation: |
          If using a Kubelet config file, edit the file to set authorization: mode to Webhook. If
          using executable arguments, edit the kubelet service file
          $kubeletsvc on each worker node and
          set the below parameter in KUBELET_AUTHZ_ARGS variable.
          --authorization-mode=Webhook
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: true

      - id: 4.2.3
        text: "Ensure that the --client-ca-file argument is set as appropriate (Scored)"
        audit: "/bin/ps -fC $kubeletbin"
        audit_config: "/bin/cat $kubeletconf"
        tests:
          test_items:
            - flag: --client-ca-file
              path: '{.authentication.x509.clientCAFile}'
              set: true
        remediation: |
          If using a Kubelet config file, edit the file to set authentication: x509: clientCAFile to
          the location of the client CA file.
          If using command line arguments, edit the kubelet service file
          $kubeletsvc on each worker node and
          set the below parameter in KUBELET_AUTHZ_ARGS variable.
          --client-ca-file=<path/to/client-ca-file>
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: true

      - id: 4.2.4
        text: "Ensure that the --read-only-port argument is set to 0 (Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."
        scored: true

      - id: 4.2.5
        text: "Ensure that the --streaming-connection-idle-timeout argument is not set to 0 (Scored)"
        audit: "/bin/ps -fC $kubeletbin"
        audit_config: "/bin/cat $kubeletconf"
        tests:
          test_items:
            - flag: --streaming-connection-idle-timeout
              path: '{.streamingConnectionIdleTimeout}'
              compare:
                op: noteq
                value: 0
            - flag: --streaming-connection-idle-timeout
              path: '{.streamingConnectionIdleTimeout}'
              set: false
          bin_op: or
        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
          $kubeletsvc 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
        scored: true

      - id: 4.2.6
        text: "Ensure that the --protect-kernel-defaults argument is set to true (Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."

      - id: 4.2.7
        text: "Ensure that the --make-iptables-util-chains argument is set to true (Scored) "
        audit: "/bin/ps -fC $kubeletbin"
        audit_config: "/bin/cat $kubeletconf"
        tests:
          test_items:
            - flag: --make-iptables-util-chains
              path: '{.makeIPTablesUtilChains}'
              compare:
                op: eq
                value: true
            - flag: --make-iptables-util-chains
              path: '{.makeIPTablesUtilChains}'
              set: false
          bin_op: or
        remediation: |
          If using a Kubelet config file, edit the file to set makeIPTablesUtilChains: true.
          If using command line arguments, edit the kubelet service file
          $kubeletsvc on each worker node and
          remove the --make-iptables-util-chains argument from the
          KUBELET_SYSTEM_PODS_ARGS variable.
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: true

      - id: 4.2.8
        text: "Ensure that the --hostname-override argument is not set (Scored)"
        audit: "/bin/ps -fC $kubeletbin "
        tests:
          test_items:
            - flag: --hostname-override
              set: false
        remediation: |
          Edit the kubelet service file $kubeletsvc
          on each worker node and remove the --hostname-override argument from the
          KUBELET_SYSTEM_PODS_ARGS variable.
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: true

      - id: 4.2.9
        text: "Ensure that the --event-qps argument is set to 0 or a level which ensures appropriate event capture (Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."

      - id: 4.2.10
        text: "Ensure that the --tls-cert-file and --tls-private-key-file arguments are set as appropriate (Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."

      - id: 4.2.11
        text: "Ensure that the --rotate-certificates argument is not set to false (Scored)"
        audit: "/bin/ps -fC $kubeletbin"
        audit_config: "/bin/cat $kubeletconf"
        tests:
          test_items:
            - flag: --rotate-certificates
              path: '{.rotateCertificates}'
              compare:
                op: eq
                value: true
            - flag: --rotate-certificates
              path: '{.rotateCertificates}'
              set: false
          bin_op: or
        remediation: |
          If using a Kubelet config file, edit the file to add the line rotateCertificates: true or
          remove it altogether to use the default value.
          If using command line arguments, edit the kubelet service file
          $kubeletsvc on each worker node and
          remove --rotate-certificates=false argument from the KUBELET_CERTIFICATE_ARGS
          variable.
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: true

      - id: 4.2.12
        text: "Ensure that the RotateKubeletServerCertificate argument is set to true (Scored)"
        audit: "/bin/ps -fC $kubeletbin"
        audit_config: "/bin/cat $kubeletconf"
        tests:
          test_items:
            - flag: RotateKubeletServerCertificate
              path: '{.featureGates.RotateKubeletServerCertificate}'
              compare:
                op: eq
                value: true
        remediation: |
          Edit the kubelet service file $kubeletsvc
          on each worker node and set the below parameter in KUBELET_CERTIFICATE_ARGS variable.
          --feature-gates=RotateKubeletServerCertificate=true
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: true

      - id: 4.2.13
        text: "Ensure that the Kubelet only makes use of Strong Cryptographic Ciphers (Not Scored)"
        type: skip
        remediation: "This control cannot be modified in GKE."
        scored: false