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Elastic Docs ›Elastic Security Solution [8.16] ›Detections and alerts ›Prebuilt rule reference

Kubernetes Suspicious Assignment of Controller Service Account

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Kubernetes Suspicious Assignment of Controller Service Account

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This rule detects a request to attach a controller service account to an existing or new pod running in the kube-system namespace. By default, controllers running as part of the API Server utilize admin-equivalent service accounts hosted in the kube-system namespace. Controller service accounts aren’t normally assigned to running pods and could indicate adversary behavior within the cluster. An attacker that can create or modify pods or pod controllers in the kube-system namespace, can assign one of these admin-equivalent service accounts to a pod and abuse their powerful token to escalate privileges and gain complete cluster control.

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
  • Execution
  • Privilege Escalation

Version: 3 (version history)

Added (Elastic Stack release): 8.5.0

Last modified (Elastic Stack release): 8.6.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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Controller service accounts aren’t normally assigned to running pods, this is abnormal behavior with very few legitimate use-cases and should result in very few false positives.

Investigation guide

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Rule query
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event.dataset : "kubernetes.audit_logs" and
kubernetes.audit.annotations.authorization_k8s_io/decision:"allow"
and kubernetes.audit.verb : "create" and
kubernetes.audit.objectRef.resource : "pods" and
kubernetes.audit.objectRef.namespace : "kube-system" and
kubernetes.audit.requestObject.spec.serviceAccountName:*controller











Threat mapping
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Framework: MITRE ATT&CKTM














Rule version history
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Version 3 (8.6.0 release)








    

  • 

    Updated query, changed from:
    

    

    

    event.dataset : "kubernetes.audit_logs" and kubernetes.audit.verb :
"create" and kubernetes.audit.objectRef.resource : "pods" and
kubernetes.audit.objectRef.namespace : "kube-system" and
kubernetes.audit.requestObject.spec.serviceAccountName:*controller
    

    

    • 




















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