Kubernetes Potential Endpoint Permission Enumeration Attempt by Anonymous User Detected

Last updated 2 days ago on 2026-02-09
Created 9 days ago on 2026-02-02

About

This rule detects potential endpoint enumeration attempts by an anonymous user. An anonymous user is a user that is not authenticated or authorized to access the Kubernetes API server. By looking for a series of failed API requests, on multiple endpoints, and a limited number of documents, this rule can detect automated permission enumeration attempts. This behavior is uncommon for regular Kubernetes clusters.
Tags
Data Source: KubernetesDomain: KubernetesUse Case: Threat DetectionTactic: DiscoveryLanguage: esql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Discovery (TA0007)(external, opens in a new tab or window)

License
Elastic License v2(external, opens in a new tab or window)

Definition

Integration Pack
Prebuilt Security Detection Rules
Related Integrations

kubernetes(external, opens in a new tab or window)

Query
text code block:
from logs-kubernetes.audit_logs-* metadata _id, _index, _version | where ( kubernetes.audit.user.username in ("system:anonymous", "system:unauthenticated") or kubernetes.audit.user.username is null or kubernetes.audit.user.username == "" ) and kubernetes.audit.level in ("RequestResponse", "ResponseComplete", "Request") | eval Esql.decision = `kubernetes.audit.annotations.authorization_k8s_io/decision` | eval Esql.code = kubernetes.audit.responseStatus.code | eval Esql.outcome = case( Esql.decision == "allow", "authz_allow", Esql.decision == "forbid", "authz_forbid", // fallback: infer from status when decision is missing Esql.code in (401, 403), "authn_authz_failed", (Esql.code >= 200 and Esql.code < 300), "success", Esql.code == 404, "not_found", Esql.code is null, "unknown", true, "other_error" ) | stats Esql.document_count = count(), Esql.authz_allow_count = sum(case(Esql.outcome == "authz_allow", 1, 0)), Esql.authz_forbid_count = sum(case(Esql.outcome == "authz_forbid", 1, 0)), Esql.status_fail_count = sum(case(Esql.outcome == "authn_authz_failed", 1, 0)), Esql.success_count = sum(case(Esql.outcome == "success", 1, 0)), Esql.not_found_count = sum(case(Esql.outcome == "not_found", 1, 0)), Esql.other_error_count = sum(case(Esql.outcome == "other_error", 1, 0)), Esql.unknown_count = sum(case(Esql.outcome == "unknown", 1, 0)), Esql.kubernetes_audit_verb_count_distinct = count_distinct(kubernetes.audit.verb), Esql.kubernetes_audit_requestURI_count_distinct = count_distinct(kubernetes.audit.requestURI), Esql.kubernetes_audit_objectRef_resource_count_distinct = count_distinct(kubernetes.audit.objectRef.resource), Esql.kubernetes_audit_outcome_values = values(Esql.outcome), Esql.kubernetes_audit_decision_values = values(Esql.decision), Esql.kubernetes_audit_responseStatus_code_values = values(Esql.code), Esql.kubernetes_audit_responseStatus_message_values = values(kubernetes.audit.responseStatus.message), Esql.kubernetes_audit_verb_values = values(kubernetes.audit.verb), Esql.kubernetes_audit_objectRef_resource_values = values(kubernetes.audit.objectRef.resource), Esql.kubernetes_audit_objectRef_namespace_values = values(kubernetes.audit.objectRef.namespace), Esql.kubernetes_audit_user_username_values = values(kubernetes.audit.user.username), Esql.kubernetes_audit_user_groups_values = values(kubernetes.audit.user.groups), Esql.kubernetes_audit_requestURI_values = values(kubernetes.audit.requestURI), Esql.data_stream_namespace_values = values(data_stream.namespace) BY kubernetes.audit.sourceIPs, kubernetes.audit.userAgent | where Esql.kubernetes_audit_requestURI_count_distinct > 5 and Esql.kubernetes_audit_objectRef_resource_count_distinct > 3 and Esql.document_count < 50 and (Esql.authz_forbid_count >= 1 or Esql.status_fail_count >= 1 or Esql.not_found_count >= 3) | keep Esql.*, kubernetes.audit.sourceIPs, kubernetes.audit.userAgent

Install detection rules in Elastic Security

Detect Kubernetes Potential Endpoint Permission Enumeration Attempt by Anonymous User Detected in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).