---
controls:
version: 1.5
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 (Scored)"
    audit: '/bin/sh -c ''if test -e $kubeletsvc; then stat -c %a $kubeletsvc; fi'' '
    tests:
      test_items:
      - flag: "644"
        set: true
        compare:
          op: eq
          value: "644"
      - flag: "640"
        set: true
        compare:
          op: eq
          value: "640"
      - flag: "600"
        set: true
        compare:
          op: eq
          value: "600"
      bin_op: or
    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 (Scored)"
    audit: '/bin/sh -c ''if test -e $kubeletsvc; then stat -c %U:%G $kubeletsvc; fi'' '
    tests:
      test_items:
      - flag: 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 $kubeletsvc 
    scored: true

  - 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 %a $proxykubeconfig; fi'' '
    tests:
      test_items:
      - flag: "644"
        set: true
        compare:
          op: eq
          value: "644"
      - flag: "640"
        set: true
        compare:
          op: eq
          value: "640"
      - flag: "600"
        set: true
        compare:
          op: eq
          value: "600"
      bin_op: or
    remediation: |
      Run the below command (based on the file location on your system) on the each worker node. 
      For example, 
      chmod 644 $proykubeconfig 
    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
        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 $proxykubeconfig 
    scored: true

  - id: 4.1.5
    text: "Ensure that the kubelet.conf file permissions are set to 644 or more restrictive (Scored)"
    audit: '/bin/sh -c ''if test -e $kubeletkubeconfig; then stat -c %a $kubeletkubeconfig; fi'' '
    tests:
      test_items:
      - flag: "644"
        set: true
        compare:
          op: eq
          value: "644"
      - flag: "640"
        set: true
        compare:
          op: eq
          value: "640"
      - flag: "600"
        set: true
        compare:
          op: eq
          value: "600"
      bin_op: or
    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 kubelet.conf file ownership is set to root:root (Scored)"
    audit: '/bin/sh -c ''if test -e $kubeletkubeconfig; then stat -c %U:%G $kubeletkubeconfig; fi'' '
    tests:
      test_items:
      - flag: root:root
        set: true
        compare:
          op: eq
          value: 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 $kubeletkubeconfig 
    scored: true

  - id: 4.1.7
    text: "Ensure that the certificate authorities file permissions are set to 644 or more restrictive (Scored)"
    types: "manual"
    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 (Scored)"
    audit: '/bin/sh -c ''if test -e $kubeletcafile; then stat -c %U:%G $kubeletcafile; fi'' '
    tests:
      test_items:
      - flag: root:root
        set: true
        compare:
          op: eq
          value: root:root
    remediation: |
      Run the following command to modify the ownership of the --client-ca-file. 
      chown root:root <filename> 
    scored: true

  - 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 %a $kubeletconf; fi'' '
    tests:
      test_items:
      - flag: "644"
        set: true
        compare:
          op: eq
          value: "644"
      - flag: "640"
        set: true
        compare:
          op: eq
          value: "640"
      - flag: "600"
        set: true
        compare:
          op: eq
          value: "600"
      bin_op: or
    remediation: |
      Run the following command (using the config file location identied 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
        set: true
    remediation: |
      Run the following command (using the config file location identied 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}'
        set: true
        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}'
        set: true
        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)"
    audit: "/bin/ps -fC $kubeletbin"      
    audit_config: "/bin/cat $kubeletconf"
    tests:
      test_items:
      - flag: "--read-only-port"
        path: '{.readOnlyPort}'
        set: true
        compare:
          op: eq
          value: 0
    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: 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}'
        set: true
        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)"
    audit: "/bin/ps -fC $kubeletbin"      
    audit_config: "/bin/cat $kubeletconf"
    tests:
      test_items:
      - flag: --protect-kernel-defaults
        path: '{.protectKernelDefaults}'
        set: true
        compare:
          op: eq
          value: true
    remediation: |
      If using a Kubelet config file, edit the file to set protectKernelDefaults: 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 (Scored) "
    audit: "/bin/ps -fC $kubeletbin"      
    audit_config: "/bin/cat $kubeletconf"
    tests:
      test_items:
      - flag: --make-iptables-util-chains
        path: '{.makeIPTablesUtilChains}'
        set: true
        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 (Not Scored)"
    # 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 "
    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 (Not Scored)"
    audit: "/bin/ps -fC $kubeletbin"      
    audit_config: "/bin/cat $kubeletconf"
    tests:
      test_items:
      - flag: --event-qps
        path: '{.eventRecordQPS}'
        set: true
        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 (Scored)"
    audit: "/bin/ps -fC $kubeletbin"      
    audit_config: "/bin/cat $kubeletconf"
    tests:
      test_items:
      - flag: --tls-cert-file
        path: '{.tlsCertFile}'
        set: true
      - flag: --tls-private-key-file
        path: '{.tlsPrivateKeyFile}'
        set: true
    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: true

  - 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}'
        set: true
        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}'
        set: true
        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)"
    audit: "/bin/ps -fC $kubeletbin"      
    audit_config: "/bin/cat $kubeletconf"
    tests:
      test_items:
      - flag: --tls-cipher-suites
        path: '{range .tlsCipherSuites[:]}{}{'',''}{end}'
        set: true
        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