Audit Policy File Not Defined

  • Query id: 13a49a2e-488e-4309-a7c0-d6b05577a5fb
  • Query name: Audit Policy File Not Defined
  • Platform: Kubernetes
  • Severity: Medium
  • Category: Observability
  • CWE: 284
  • URL: Github

Description

When using kube-apiserver command, the '--audit-policy-file' flag should be defined
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file
apiVersion: v1
kind: Pod
metadata:
  name: command-demo
  labels:
    purpose: demonstrate-command
spec:
  containers:
    - name: command-demo-container
      image: gcr.io/google_containers/kube-apiserver-amd64:v1.6.0
      command: ["kube-apiserver"]
      args: []
  restartPolicy: OnFailure
Positive test num. 2 - yaml file
apiVersion: v1
kind: Pod
metadata:
  name: command-demo
  labels:
    purpose: demonstrate-command
spec:
  containers:
    - name: command-demo-container
      image: gcr.io/google_containers/kube-apiserver-amd64:v1.6.0
      command: ["kube-apiserver","--audit-policy-file=./not/valid/file.yaml"]
      args: []
  restartPolicy: OnFailure
Positive test num. 3 - yaml file
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: dummy
  namespace: knative-sequence
spec:
  template:
    spec:
      containers:
      - name: command-demo-container
        image: gcr.io/google_containers/kube-apiserver-amd64:v1.6.0
        command: ["kube-apiserver"]
        args: []
    restartPolicy: OnFailure

Code samples without security vulnerabilities

Negative test num. 1 - yaml file
apiVersion: v1
kind: Pod
metadata:
  name: command-demo
  labels:
    purpose: demonstrate-command
spec:
  containers:
    - name: command-demo-container
      image: gcr.io/google_containers/kube-apiserver-amd64:v1.6.0
      command: ["kube-apiserver"]
      args: ["--audit-policy-file=/home/foo/cx/kics/assets/queries/k8s/audit_policy_file_not_defined/test/negative1.yaml"]
  restartPolicy: OnFailure
---
apiVersion: audit.k8s.io/v1 # This is required.
kind: Policy
# Don't generate audit events for all requests in RequestReceived stage.
omitStages:
  - "RequestReceived"
rules:
  # Log pod changes at RequestResponse level
  - level: RequestResponse
    resources:
    - group: ""
      # Resource "pods" doesn't match requests to any subresource of pods,
      # which is consistent with the RBAC policy.
      resources: ["pods"]
  # Log "pods/log", "pods/status" at Metadata level
  - level: Metadata
    resources:
    - group: ""
      resources: ["pods/log", "pods/status"]

  # Don't log requests to a configmap called "controller-leader"
  - level: None
    resources:
    - group: ""
      resources: ["configmaps"]
      resourceNames: ["controller-leader"]

  # Don't log watch requests by the "system:kube-proxy" on endpoints or services
  - level: None
    users: ["system:kube-proxy"]
    verbs: ["watch"]
    resources:
    - group: "" # core API group
      resources: ["endpoints", "services"]

  # Don't log authenticated requests to certain non-resource URL paths.
  - level: None
    userGroups: ["system:authenticated"]
    nonResourceURLs:
    - "/api*" # Wildcard matching.
    - "/version"

  # Log the request body of configmap changes in kube-system.
  - level: Request
    resources:
    - group: "" # core API group
      resources: ["configmaps"]
    # This rule only applies to resources in the "kube-system" namespace.
    # The empty string "" can be used to select non-namespaced resources.
    namespaces: ["kube-system"]

  # Log configmap and secret changes in all other namespaces at the Metadata level.
  - level: Metadata
    resources:
    - group: "" # core API group
      resources: ["secrets", "configmaps"]

  # Log all other resources in core and extensions at the Request level.
  - level: Request
    resources:
    - group: "" # core API group
    - group: "extensions" # Version of group should NOT be included.

  # A catch-all rule to log all other requests at the Metadata level.
  - level: Metadata
    # Long-running requests like watches that fall under this rule will not
    # generate an audit event in RequestReceived.
    omitStages:
      - "RequestReceived"
Negative test num. 2 - yaml file
apiVersion: v1
kind: Pod
metadata:
  name: command-demo
  labels:
    purpose: demonstrate-command
spec:
  containers:
    - name: command-demo-container
      image: gcr.io/google_containers/kube-apiserver-amd64:v1.6.0
      command: ["kube-apiserver","--audit-policy-file=/home/foo/cx/kics/assets/queries/k8s/audit_policy_file_not_defined/test/negative2.yaml"]
      args: []
  restartPolicy: OnFailure
---
apiVersion: audit.k8s.io/v1 # This is required.
kind: Policy
# Don't generate audit events for all requests in RequestReceived stage.
omitStages:
  - "RequestReceived"
rules:
  # Log pod changes at RequestResponse level
  - level: RequestResponse
    resources:
    - group: ""
      # Resource "pods" doesn't match requests to any subresource of pods,
      # which is consistent with the RBAC policy.
      resources: ["pods"]
  # Log "pods/log", "pods/status" at Metadata level
  - level: Metadata
    resources:
    - group: ""
      resources: ["pods/log", "pods/status"]

  # Don't log requests to a configmap called "controller-leader"
  - level: None
    resources:
    - group: ""
      resources: ["configmaps"]
      resourceNames: ["controller-leader"]

  # Don't log watch requests by the "system:kube-proxy" on endpoints or services
  - level: None
    users: ["system:kube-proxy"]
    verbs: ["watch"]
    resources:
    - group: "" # core API group
      resources: ["endpoints", "services"]

  # Don't log authenticated requests to certain non-resource URL paths.
  - level: None
    userGroups: ["system:authenticated"]
    nonResourceURLs:
    - "/api*" # Wildcard matching.
    - "/version"

  # Log the request body of configmap changes in kube-system.
  - level: Request
    resources:
    - group: "" # core API group
      resources: ["configmaps"]
    # This rule only applies to resources in the "kube-system" namespace.
    # The empty string "" can be used to select non-namespaced resources.
    namespaces: ["kube-system"]

  # Log configmap and secret changes in all other namespaces at the Metadata level.
  - level: Metadata
    resources:
    - group: "" # core API group
      resources: ["secrets", "configmaps"]

  # Log all other resources in core and extensions at the Request level.
  - level: Request
    resources:
    - group: "" # core API group
    - group: "extensions" # Version of group should NOT be included.

  # A catch-all rule to log all other requests at the Metadata level.
  - level: Metadata
    # Long-running requests like watches that fall under this rule will not
    # generate an audit event in RequestReceived.
    omitStages:
      - "RequestReceived"