kyverno/test/best_practices/disallow_sysctls.yaml

---
apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  annotations:
    policies.kyverno.io/category: Security
    policies.kyverno.io/description: The Sysctl interface allows modifications to
      kernel parameters at runtime. In a Kubernetes pod these parameters can be specified
      under `securityContext.sysctls`. Kernel parameter modifications can be used
      for exploits and should be restricted.
  name: disallow-sysctls
spec:
  admission: true
  background: true
  rules:
  - match:
      any:
      - resources:
          kinds:
          - Pod
    name: validate-sysctls
    validate:
      message: Changes to kernel parameters are not allowed
      pattern:
        spec:
          =(securityContext):
            X(sysctls): null
  validationFailureAction: Audit