Elastic medium stable kql

GKE Admission Webhook Created or Modified

Detects creation or modification of GKE mutating or validating admission webhook configurations by non-system identities. Malicious webhooks can inject workloads, block security tooling, or intercept API traffic for persistence and defense evasion.

View Source

Detection Logic

data_stream.dataset:gcp.audit and event.outcome:success and event.action:(
  "io.k8s.admissionregistration.v1.mutatingwebhookconfigurations.create" or
  "io.k8s.admissionregistration.v1.mutatingwebhookconfigurations.update" or
  "io.k8s.admissionregistration.v1.mutatingwebhookconfigurations.patch" or
  "io.k8s.admissionregistration.v1.validatingwebhookconfigurations.create" or
  "io.k8s.admissionregistration.v1.validatingwebhookconfigurations.update" or
  "io.k8s.admissionregistration.v1.validatingwebhookconfigurations.patch"
) and not user.email:(
  "system:kube-controller-manager" or "system:kube-scheduler" or system\:serviceaccount\:kube-system\:* or
  system\:serviceaccount\:gke-managed-system\:* or system\:serviceaccount\:cert-manager\:* or
  system\:serviceaccount\:gatekeeper-system\:* or system\:serviceaccount\:kyverno\:* or "system:addon-manager" or
  *-operator or *-cainjector or *-webhook or *argocd* or "system:gke-common-webhooks"
)

False Positives

⚠ GitOps and platform controllers (cert-manager, Gatekeeper, Kyverno, service mesh) legitimately manage webhooks. Validate change tickets and controller identities before tuning.

Field Validations

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