kube-bench/cfg/k3s-cis-1.23/node.yaml

---
controls:
version: "k3s-cis-1.23"
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 (Automated)"
        audit: '/bin/sh -c ''if test -e $kubeletsvc; then stat -c permissions=%a $kubeletsvc; fi'' '
        type: "skip"
        tests:
          test_items:
            - flag: "permissions"
              compare:
                op: bitmask
                value: "644"
        remediation: |
          Run the below command (based on the file location on your system) on the each worker node.
          For example, chmod 644 $kubeletsvc
        scored: true

      - id: 4.1.2
        text: "Ensure that the kubelet service file ownership is set to root:root (Automated)"
        audit: '/bin/sh -c ''if test -e $kubeletsvc; then stat -c %U:%G $kubeletsvc; fi'' '
        type: "skip"
        tests:
          test_items:
            - flag: root:root
        remediation: |
          Run the below command (based on the file location on your system) on the each worker node.
          For example,
          chown root:root $kubeletsvc
        scored: true

      - id: 4.1.3
        text: "If proxy kubeconfig file exists ensure permissions are set to 644 or more restrictive (Manual)"
        audit: 'stat -c %a /var/lib/rancher/k3s/agent/kubeproxy.kubeconfig'
        tests:
          bin_op: or
          test_items:
            - flag: "permissions"
              set: true
              compare:
                op: bitmask
                value: "644"
        remediation: |
          Run the below command (based on the file location on your system) on the each worker node.
          For example,
          chmod 644 $proxykubeconfig
        scored: false

      - id: 4.1.4
        text: "If proxy kubeconfig file exists ensure ownership is set to root:root (Manual)"
        audit: '/bin/sh -c ''if test -e /var/lib/rancher/k3s/agent/kubeproxy.kubeconfig; then stat -c %U:%G /var/lib/rancher/k3s/agent/kubeproxy.kubeconfig; fi'' '
        tests:
          bin_op: or
          test_items:
            - flag: root:root
        remediation: |
          Run the below command (based on the file location on your system) on the each worker node.
          For example, chown root:root $proxykubeconfig
        scored: false

      - id: 4.1.5
        text: "Ensure that the --kubeconfig kubelet.conf file permissions are set to 644 or more restrictive (Automated)"
        audit: 'stat -c %a /var/lib/rancher/k3s/agent/kubelet.kubeconfig '
        tests:
          test_items:
            - flag: "644"
              compare:
                op: eq
                value: "644"
              set: true
        remediation: |
          Run the below command (based on the file location on your system) on the each worker node.
          For example,
          chmod 644 $kubeletkubeconfig
        scored: true

      - id: 4.1.6
        text: "Ensure that the --kubeconfig kubelet.conf file ownership is set to root:root (Automated)"
        audit: 'stat -c %U:%G /var/lib/rancher/k3s/agent/kubelet.kubeconfig'
        tests:
          test_items:
            - flag: "root:root"
              compare:
                op: eq
                value: "root:root"
              set: true
        remediation: |
          Run the below command (based on the file location on your system) on the each worker node.
          For example,
          chown root:root $kubeletkubeconfig
        scored: true

      - id: 4.1.7
        text: "Ensure that the certificate authorities file permissions are set to 644 or more restrictive (Manual)"
        audit: "stat -c %a /var/lib/rancher/k3s/server/tls/server-ca.crt"
        tests:
          test_items:
            - flag: "644"
              compare:
                op: eq
                value: "644"
              set: true
            - flag: "640"
              compare:
                op: eq
                value: "640"
              set: true
            - flag: "600"
              compare:
                op: eq
                value: "600"
              set: true
            - flag: "444"
              compare:
                op: eq
                value: "444"
              set: true
            - flag: "440"
              compare:
                op: eq
                value: "440"
              set: true
            - flag: "400"
              compare:
                op: eq
                value: "400"
              set: true
            - flag: "000"
              compare:
                op: eq
                value: "000"
              set: true
          bin_op: or
        remediation: |
          Run the following command to modify the file permissions of the
          --client-ca-file chmod 644 <filename>
        scored: true

      - id: 4.1.8
        text: "Ensure that the client certificate authorities file ownership is set to root:root (Manual)"
        audit: "stat -c %U:%G /var/lib/rancher/k3s/server/tls/client-ca.crt"
        tests:
          test_items:
            - flag: root:root
        remediation: |
          Run the following command to modify the ownership of the --client-ca-file.
          chown root:root <filename>
        scored: false

      - id: 4.1.9
        text: "Ensure that the kubelet --config configuration file has permissions set to 644 or more restrictive (Automated)"
        audit: '/bin/sh -c ''if test -e $kubeletconf; then stat -c permissions=%a $kubeletconf; fi'' '
        type: "skip"
        tests:
          test_items:
            - flag: "permissions"
              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 --config configuration file ownership is set to root:root (Automated)"
        audit: '/bin/sh -c ''if test -e $kubeletconf; then stat -c %U:%G $kubeletconf; fi'' '
        type: "skip"
        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 (Automated)"
        audit: '/bin/sh -c ''if test $(journalctl -m -u k3s | grep "Running kube-apiserver" | wc -l) -gt 0; then journalctl -m -u k3s | grep "Running kube-apiserver" | tail -n1 | grep "anonymous-auth" | grep -v grep; else echo "--anonymous-auth=false"; fi'' '
        tests:
          test_items:
            - flag: "--anonymous-auth"
              path: '{.authentication.anonymous.enabled}'
              compare:
                op: eq
                value: false
              set: true
        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 (Automated)"
        audit: '/bin/sh -c ''if test $(journalctl -m -u k3s | grep "Running kube-apiserver" | wc -l) -gt 0; then journalctl -m -u k3s | grep "Running kube-apiserver" | tail -n1 | grep "authorization-mode" | grep -v grep; else echo "--authorization-mode=Webhook"; fi'' '
        tests:
          test_items:
            - flag: --authorization-mode
              path: '{.authorization.mode}'
              compare:
                op: nothave
                value: AlwaysAllow
              set: true
        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 (Automated)"
        audit: '/bin/sh -c ''if test $(journalctl -m -u k3s | grep "Running kube-apiserver" | wc -l) -gt 0; then journalctl -m -u k3s | grep "Running kube-apiserver" | tail -n1 | grep "client-ca-file" | grep -v grep; else echo "--client-ca-file=/var/lib/rancher/k3s/server/tls/request-header-ca.crt"; fi'' '
        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 (Manual)"
        audit: "journalctl -m -u k3s | grep 'Running kubelet' | tail -n1 | grep 'read-only-port' "
        tests:
          bin_op: or
          test_items:
            - flag: "--read-only-port"
              path: '{.readOnlyPort}'
              compare:
                op: eq
                value: 0
            - flag: "--read-only-port"
              path: '{.readOnlyPort}'
              set: false
        remediation: |
          If using a Kubelet config file, edit the file to set `readOnlyPort` to 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.
          --read-only-port=0
          Based on your system, restart the kubelet service. For example,
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: false

      - id: 4.2.5
        text: "Ensure that the --streaming-connection-idle-timeout argument is not set to 0 (Manual)"
        audit: "journalctl -m -u k3s | grep 'Running kubelet' | tail -n1 | grep 'streaming-connection-idle-timeout'"
        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: false

      - id: 4.2.6
        text: "Ensure that the --protect-kernel-defaults argument is set to true (Automated)"
        audit: "journalctl -m -u k3s | grep 'Running kubelet' | tail -n1 | grep 'protect-kernel-defaults'"
        type: "skip"
        tests:
          test_items:
            - flag: --protect-kernel-defaults
              path: '{.protectKernelDefaults}'
              compare:
                op: eq
                value: true
              set: true
        remediation: |
          If using a Kubelet config file, edit the file to set `protectKernelDefaults` to `true`.
          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.
          --protect-kernel-defaults=true
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: true

      - id: 4.2.7
        text: "Ensure that the --make-iptables-util-chains argument is set to true (Automated)"
        audit: "journalctl -m -u k3s | grep 'Running kubelet' | tail -n1 | grep 'make-iptables-util-chains'"
        type: "skip"
        tests:
          test_items:
            - flag: --make-iptables-util-chains
              path: '{.makeIPTablesUtilChains}'
              compare:
                op: eq
                value: true
              set: 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` to `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 (Manual)"
        # This is one of those properties that can only be set as a command line argument.
        # To check if the property is set as expected, we need to parse the kubelet command
        # instead reading the Kubelet Configuration file.
        audit: "/bin/ps -fC $kubeletbin "
        type: "skip"
        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: false

      - id: 4.2.9
        text: "Ensure that the --event-qps argument is set to 0 or a level which ensures appropriate event capture (Manual)"
        audit: "/bin/ps -fC $kubeletbin"
        type: "manual"
        tests:
          test_items:
            - flag: --event-qps
              path: '{.eventRecordQPS}'
              compare:
                op: eq
                value: 0
        remediation: |
          If using a Kubelet config file, edit the file to set `eventRecordQPS` to an appropriate level.
          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.
          Based on your system, restart the kubelet service. For example,
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: false

      - id: 4.2.10
        text: "Ensure that the --tls-cert-file and --tls-private-key-file arguments are set as appropriate (Manual)"
        audit: "journalctl -m -u k3s | grep 'Running kubelet' | tail -n1"
        tests:
          test_items:
            - flag: --tls-cert-file
              path: '/var/lib/rancher/k3s/agent/serving-kubelet.crt'
            - flag: --tls-private-key-file
              path: '/var/lib/rancher/k3s/agent/serving-kubelet.key'
        remediation: |
          If using a Kubelet config file, edit the file to set `tlsCertFile` to the location
          of the certificate file to use to identify this Kubelet, and `tlsPrivateKeyFile`
          to the location of the corresponding private key file.
          If using command line arguments, edit the kubelet service file
          $kubeletsvc on each worker node and
          set the below parameters in KUBELET_CERTIFICATE_ARGS variable.
          --tls-cert-file=<path/to/tls-certificate-file>
          --tls-private-key-file=<path/to/tls-key-file>
          Based on your system, restart the kubelet service. For example,
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: false

      - id: 4.2.11
        text: "Ensure that the --rotate-certificates argument is not set to false (Automated)"
        audit: "/bin/ps -fC $kubeletbin"
        type: "skip"
        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` to `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: "Verify that the RotateKubeletServerCertificate argument is set to true (Manual)"
        audit: "/bin/ps -fC $kubeletbin"
        type: "skip"
        tests:
          bin_op: or
          test_items:
            - flag: RotateKubeletServerCertificate
              path: '{.featureGates.RotateKubeletServerCertificate}'
              compare:
                op: nothave
                value: false
            - flag: RotateKubeletServerCertificate
              path: '{.featureGates.RotateKubeletServerCertificate}'
              set: false
        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: false

      - id: 4.2.13
        text: "Ensure that the Kubelet only makes use of Strong Cryptographic Ciphers (Manual)"
        audit: "/bin/ps -fC $kubeletbin"
        type: "manual"
        tests:
          test_items:
            - flag: --tls-cipher-suites
              path: '{range .tlsCipherSuites[:]}{}{'',''}{end}'
              compare:
                op: valid_elements
                value: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256
        remediation: |
          If using a Kubelet config file, edit the file to set `tlsCipherSuites` to
          TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256
          or to a subset of these values.
          If using executable arguments, edit the kubelet service file
          $kubeletsvc on each worker node and
          set the --tls-cipher-suites parameter as follows, or to a subset of these values.
          --tls-cipher-suites=TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256
          Based on your system, restart the kubelet service. For example:
          systemctl daemon-reload
          systemctl restart kubelet.service
        scored: false