Kubernetes Denied Service Account Requestedit

This rule detects when a service account makes an unauthorized request for resources from the API server. Service accounts follow a very predictable pattern of behavior. A service account should never send an unauthorized request to the API server. This behavior is likely an indicator of compromise or of a problem within the cluster. An adversary may have gained access to credentials/tokens and this could be an attempt to access or create resources to facilitate further movement or execution within the cluster.

Rule type: query

Rule indices:

  • logs-kubernetes.*

Severity: medium

Risk score: 47

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Kubernetes
  • Continuous Monitoring
  • Discovery

Version: 1

Added (Elastic Stack release): 8.5.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positivesedit

Unauthorized requests from service accounts are highly abnormal and more indicative of human behavior or a serious problem within the cluster. This behavior should be investigated further.

Investigation guideedit


Rule queryedit

event.dataset: "kubernetes.audit_logs" and
kubernetes.audit.user.username: system\:serviceaccount\:* and
kubernetes.audit.annotations.authorization_k8s_io/decision: "forbid"

Threat mappingedit

Framework: MITRE ATT&CKTM