---
controls:
version: "cis-1.9"
id: 5
text: "Kubernetes Policies"
type: "policies"
groups:
  - id: 5.1
    text: "RBAC and Service Accounts"
    checks:
      - id: 5.1.1
        text: "Ensure that the cluster-admin role is only used where required (Automated)"
        audit: |
          kubectl get clusterrolebindings -o=custom-columns=NAME:.metadata.name,ROLE:.roleRef.name,SUBJECT:.subjects[*].name --no-headers | while read -r role_name role_binding subject
          do
            if [[ "${role_name}" != "cluster-admin" && "${role_binding}" == "cluster-admin" ]]; then
              is_compliant="false"
            else
              is_compliant="true"
            fi;
            echo "**role_name: ${role_name} role_binding: ${role_binding} subject: ${subject} is_compliant: ${is_compliant}"
          done
        use_multiple_values: true
        tests:
          test_items:
            - flag: "is_compliant"
              compare:
                op: eq
                value: true
        remediation: |
          Identify all clusterrolebindings to the cluster-admin role. Check if they are used and
          if they need this role or if they could use a role with fewer privileges.
          Where possible, first bind users to a lower privileged role and then remove the
          clusterrolebinding to the cluster-admin role : kubectl delete clusterrolebinding [name]
          Condition: is_compliant is false if rolename is not cluster-admin and rolebinding is cluster-admin.
        scored: false

      - id: 5.1.2
        text: "Minimize access to secrets (Automated)"
        audit: "echo \"canGetListWatchSecretsAsSystemAuthenticated: $(kubectl auth can-i get,list,watch secrets --all-namespaces --as=system:authenticated)\""
        tests:
          test_items:
            - flag: "canGetListWatchSecretsAsSystemAuthenticated"
              compare:
                op: eq
                value: no
        remediation: |
          Where possible, remove get, list and watch access to Secret objects in the cluster.
        scored: false

      - id: 5.1.3
        text: "Minimize wildcard use in Roles and ClusterRoles (Automated)"
        audit: |
          # Check Roles
          kubectl get roles --all-namespaces -o custom-columns=ROLE_NAMESPACE:.metadata.namespace,ROLE_NAME:.metadata.name --no-headers | while read -r role_namespace role_name
          do
            role_rules=$(kubectl get role -n "${role_namespace}" "${role_name}" -o=json | jq -c '.rules')
            if echo "${role_rules}" | grep -q "\[\"\*\"\]"; then
              role_is_compliant="false"
            else
              role_is_compliant="true"
            fi;
            echo "**role_name: ${role_name} role_namespace: ${role_namespace} role_rules: ${role_rules} role_is_compliant: ${role_is_compliant}"
          done

          # Check ClusterRoles
          kubectl get clusterroles -o custom-columns=CLUSTERROLE_NAME:.metadata.name --no-headers | while read -r clusterrole_name
          do
            clusterrole_rules=$(kubectl get clusterrole "${clusterrole_name}" -o=json | jq -c '.rules')
            if echo "${clusterrole_rules}" | grep -q "\[\"\*\"\]"; then
              clusterrole_is_compliant="false"
            else
              clusterrole_is_compliant="true"
            fi;
          echo "**clusterrole_name: ${clusterrole_name} clusterrole_rules: ${clusterrole_rules} clusterrole_is_compliant: ${clusterrole_is_compliant}"
          done
        use_multiple_values: true
        tests:
          bin_op: or
          test_items:
            - flag: "role_is_compliant"
              compare:
                op: eq
                value: true
              set: true
            - flag: "clusterrole_is_compliant"
              compare:
                op: eq
                value: true
              set: true
        remediation: |
          Where possible replace any use of wildcards ["*"] in roles and clusterroles with specific
          objects or actions.
          Condition: role_is_compliant is false if ["*"] is found in rules.
          Condition: clusterrole_is_compliant is false if ["*"] is found in rules.
        scored: false

      - id: 5.1.4
        text: "Minimize access to create pods (Automated)"
        audit: |
          echo "canCreatePodsAsSystemAuthenticated: $(kubectl auth can-i create pods --all-namespaces --as=system:authenticated)"
        tests:
          test_items:
            - flag: "canCreatePodsAsSystemAuthenticated"
              compare:
                op: eq
                value: no
        remediation: |
          Where possible, remove create access to pod objects in the cluster.
        scored: false
      - id: 5.1.5
        text: "Ensure that default service accounts are not actively used (Automated)"
        audit: |
          kubectl get serviceaccount --all-namespaces --field-selector metadata.name=default -o=json | jq -r '.items[] | " namespace: \(.metadata.namespace), kind: \(.kind), name: \(.metadata.name), automountServiceAccountToken: \(.automountServiceAccountToken | if . == null then "notset" else . end )"' | xargs -L 1
        use_multiple_values: true
        tests:
          test_items:
            - flag: "automountServiceAccountToken"
              compare:
                op: eq
                value: false
              set: true
        remediation: |
          Create explicit service accounts wherever a Kubernetes workload requires specific access
          to the Kubernetes API server.
          Modify the configuration of each default service account to include this value
          `automountServiceAccountToken: false`.
        scored: false

      - id: 5.1.6
        text: "Ensure that Service Account Tokens are only mounted where necessary (Automated)"
        audit: |
          kubectl get pods --all-namespaces -o custom-columns=POD_NAMESPACE:.metadata.namespace,POD_NAME:.metadata.name,POD_SERVICE_ACCOUNT:.spec.serviceAccount,POD_IS_AUTOMOUNTSERVICEACCOUNTTOKEN:.spec.automountServiceAccountToken --no-headers | while read -r pod_namespace pod_name pod_service_account pod_is_automountserviceaccounttoken
          do
            # Retrieve automountServiceAccountToken's value for ServiceAccount and Pod, set to notset if null or <none>.
            svacc_is_automountserviceaccounttoken=$(kubectl get serviceaccount -n "${pod_namespace}" "${pod_service_account}" -o json | jq -r '.automountServiceAccountToken' | sed -e 's/<none>/notset/g' -e 's/null/notset/g')
            pod_is_automountserviceaccounttoken=$(echo "${pod_is_automountserviceaccounttoken}" | sed -e 's/<none>/notset/g' -e 's/null/notset/g')
            if [ "${svacc_is_automountserviceaccounttoken}" = "false" ] && ( [ "${pod_is_automountserviceaccounttoken}" = "false" ] || [ "${pod_is_automountserviceaccounttoken}" = "notset" ] ); then
              is_compliant="true"
            elif [ "${svacc_is_automountserviceaccounttoken}" = "true" ] && [ "${pod_is_automountserviceaccounttoken}" = "false" ]; then
              is_compliant="true"
            else
              is_compliant="false"
            fi
            echo "**namespace: ${pod_namespace} pod_name: ${pod_name} service_account: ${pod_service_account} pod_is_automountserviceaccounttoken: ${pod_is_automountserviceaccounttoken} svacc_is_automountServiceAccountToken: ${svacc_is_automountserviceaccounttoken} is_compliant: ${is_compliant}"
          done
        use_multiple_values: true
        tests:
          test_items:
            - flag: "is_compliant"
              compare:
                op: eq
                value: true
        remediation: |
          Modify the definition of ServiceAccounts and Pods which do not need to mount service
          account tokens to disable it, with `automountServiceAccountToken: false`.
          If both the ServiceAccount and the Pod's .spec specify a value for automountServiceAccountToken, the Pod spec takes precedence.
          Condition: Pod is_compliant to true when
            - ServiceAccount is automountServiceAccountToken: false and Pod is automountServiceAccountToken: false or notset
            - ServiceAccount is automountServiceAccountToken: true notset and Pod is automountServiceAccountToken: false
        scored: false

      - id: 5.1.7
        text: "Avoid use of system:masters group (Manual)"
        type: "manual"
        remediation: |
          Remove the system:masters group from all users in the cluster.
        scored: false

      - id: 5.1.8
        text: "Limit use of the Bind, Impersonate and Escalate permissions in the Kubernetes cluster (Manual)"
        type: "manual"
        remediation: |
          Where possible, remove the impersonate, bind and escalate rights from subjects.
        scored: false

      - id: 5.1.9
        text: "Minimize access to create persistent volumes (Manual)"
        type: "manual"
        remediation: |
          Where possible, remove create access to PersistentVolume objects in the cluster.
        scored: false

      - id: 5.1.10
        text: "Minimize access to the proxy sub-resource of nodes (Manual)"
        type: "manual"
        remediation: |
          Where possible, remove access to the proxy sub-resource of node objects.
        scored: false

      - id: 5.1.11
        text: "Minimize access to the approval sub-resource of certificatesigningrequests objects (Manual)"
        type: "manual"
        remediation: |
          Where possible, remove access to the approval sub-resource of certificatesigningrequest objects.
        scored: false

      - id: 5.1.12
        text: "Minimize access to webhook configuration objects (Manual)"
        type: "manual"
        remediation: |
          Where possible, remove access to the validatingwebhookconfigurations or mutatingwebhookconfigurations objects
        scored: false

      - id: 5.1.13
        text: "Minimize access to the service account token creation (Manual)"
        type: "manual"
        remediation: |
          Where possible, remove access to the token sub-resource of serviceaccount objects.
        scored: false

  - id: 5.2
    text: "Pod Security Standards"
    checks:
      - id: 5.2.1
        text: "Ensure that the cluster has at least one active policy control mechanism in place (Manual)"
        type: "manual"
        remediation: |
          Ensure that either Pod Security Admission or an external policy control system is in place
          for every namespace which contains user workloads.
        scored: false

      - id: 5.2.2
        text: "Minimize the admission of privileged containers (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of privileged containers.
        scored: false

      - id: 5.2.3
        text: "Minimize the admission of containers wishing to share the host process ID namespace (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of `hostPID` containers.
        scored: false

      - id: 5.2.4
        text: "Minimize the admission of containers wishing to share the host IPC namespace (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of `hostIPC` containers.
        scored: false

      - id: 5.2.5
        text: "Minimize the admission of containers wishing to share the host network namespace (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of `hostNetwork` containers.
        scored: false

      - id: 5.2.6
        text: "Minimize the admission of containers with allowPrivilegeEscalation (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of containers with `.spec.allowPrivilegeEscalation` set to `true`.
        scored: false

      - id: 5.2.7
        text: "Minimize the admission of root containers (Manual)"
        type: "manual"
        remediation: |
          Create a policy for each namespace in the cluster, ensuring that either `MustRunAsNonRoot`
          or `MustRunAs` with the range of UIDs not including 0, is set.
        scored: false

      - id: 5.2.8
        text: "Minimize the admission of containers with the NET_RAW capability (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of containers with the `NET_RAW` capability.
        scored: false

      - id: 5.2.9
        text: "Minimize the admission of containers with added capabilities (Manual)"
        type: "manual"
        remediation: |
          Ensure that `allowedCapabilities` is not present in policies for the cluster unless
          it is set to an empty array.
        scored: false

      - id: 5.2.10
        text: "Minimize the admission of containers with capabilities assigned (Manual)"
        type: "manual"
        remediation: |
          Review the use of capabilites in applications running on your cluster. Where a namespace
          contains applications which do not require any Linux capabities to operate consider adding
          a PSP which forbids the admission of containers which do not drop all capabilities.
        scored: false

      - id: 5.2.11
        text: "Minimize the admission of Windows HostProcess containers (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of containers that have `.securityContext.windowsOptions.hostProcess` set to `true`.
        scored: false

      - id: 5.2.12
        text: "Minimize the admission of HostPath volumes (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of containers with `hostPath` volumes.
        scored: false

      - id: 5.2.13
        text: "Minimize the admission of containers which use HostPorts (Manual)"
        type: "manual"
        remediation: |
          Add policies to each namespace in the cluster which has user workloads to restrict the
          admission of containers which use `hostPort` sections.
        scored: false

  - id: 5.3
    text: "Network Policies and CNI"
    checks:
      - id: 5.3.1
        text: "Ensure that the CNI in use supports NetworkPolicies (Manual)"
        type: "manual"
        remediation: |
          If the CNI plugin in use does not support network policies, consideration should be given to
          making use of a different plugin, or finding an alternate mechanism for restricting traffic
          in the Kubernetes cluster.
        scored: false

      - id: 5.3.2
        text: "Ensure that all Namespaces have NetworkPolicies defined (Manual)"
        type: "manual"
        remediation: |
          Follow the documentation and create NetworkPolicy objects as you need them.
        scored: false

  - id: 5.4
    text: "Secrets Management"
    checks:
      - id: 5.4.1
        text: "Prefer using Secrets as files over Secrets as environment variables (Manual)"
        type: "manual"
        remediation: |
          If possible, rewrite application code to read Secrets from mounted secret files, rather than
          from environment variables.
        scored: false

      - id: 5.4.2
        text: "Consider external secret storage (Manual)"
        type: "manual"
        remediation: |
          Refer to the Secrets management options offered by your cloud provider or a third-party
          secrets management solution.
        scored: false

  - id: 5.5
    text: "Extensible Admission Control"
    checks:
      - id: 5.5.1
        text: "Configure Image Provenance using ImagePolicyWebhook admission controller (Manual)"
        type: "manual"
        remediation: |
          Follow the Kubernetes documentation and setup image provenance.
        scored: false

  - id: 5.7
    text: "General Policies"
    checks:
      - id: 5.7.1
        text: "Create administrative boundaries between resources using namespaces (Manual)"
        type: "manual"
        remediation: |
          Follow the documentation and create namespaces for objects in your deployment as you need
          them.
        scored: false

      - id: 5.7.2
        text: "Ensure that the seccomp profile is set to docker/default in your Pod definitions (Manual)"
        type: "manual"
        remediation: |
          Use `securityContext` to enable the docker/default seccomp profile in your pod definitions.
          An example is as below:
            securityContext:
              seccompProfile:
                type: RuntimeDefault
        scored: false

      - id: 5.7.3
        text: "Apply SecurityContext to your Pods and Containers (Manual)"
        type: "manual"
        remediation: |
          Follow the Kubernetes documentation and apply SecurityContexts to your Pods. For a
          suggested list of SecurityContexts, you may refer to the CIS Security Benchmark for Docker
          Containers.
        scored: false

      - id: 5.7.4
        text: "The default namespace should not be used (Manual)"
        type: "manual"
        remediation: |
          Ensure that namespaces are created to allow for appropriate segregation of Kubernetes
          resources and that all new resources are created in a specific namespace.
        scored: false
