GCP Audit Logs: Access Context Manager Access Policy Deletion

Flags GCP Access Context Manager audit events where granted access policy delete permissions occur.

FreeReviewedSigma · Medium · v5

Product: gcp
Service: gcp.audit
Author: Bryan Lim (SigmaHQ), DRL 1.1
Published: 2024-01-12
Updated: 2026-07-31

ATT&CK techniques

Persistence → Priv Esc

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1098Account Manipulation
Priv Esc
- T1098Account Manipulation
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags GCP Access Context Manager audit events where an access policy or related objects are deleted by a caller with granted authorization. Deleting access policies can remove enforcement and may enable an attacker to gain or expand access to protected GCP resources. It relies on GCP audit log telemetry from the accesscontextmanager.googleapis.com service and matches specific delete permissions with granted=true in protoPayload authorizationInfo.

Reporting behind it

Related detections9 linkedT1098 — drag to rearrange

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Malicious Modification of a Computer Account SPN (via security)

Suspicious Massive Group Membership Changes (via security)

Malicious High Risk Active Directory Group Membership Change (via security)

Malicious Account Marked as Sensitive and Cannot Be Delegated Had Its Protection Removed (via security)

Malicious Host Constrained Delegation Settings Changed for Potential Abuse (Rubeus) - Kerberos Only (via security)

Malicious Host Set with Unconstrained Delegation (via security)

GCP Audit Logs: Access Context Manager Access Policy Deletion

Pivot detection · T1098 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

gcp-access-policy-deletion-via-accesscontextmanager-audit-logs-32438676

title: "GCP Audit Logs: Access Context Manager Access Policy Deletion"
id: 7b13bf52-14cd-49e4-8583-42aba3a1ac8f
status: test
description: This rule flags GCP Access Context Manager audit events where an access policy or related objects are deleted by a caller with granted authorization. Deleting access policies can remove enforcement and may enable an attacker to gain or expand access to protected GCP resources. It relies on GCP audit log telemetry from the accesscontextmanager.googleapis.com service and matches specific delete permissions with granted=true in protoPayload authorizationInfo.
references:
  - https://cloud.google.com/access-context-manager/docs/audit-logging
  - https://cloud.google.com/logging/docs/audit/understanding-audit-logs
  - https://cloud.google.com/logging/docs/reference/audit/auditlog/rest/Shared.Types/AuditLog
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/gcp/audit/gcp_access_policy_deleted.yml
author: Bryan Lim, Huntrule Team
date: 2024-01-12
tags:
  - attack.persistence
  - attack.privilege-escalation
  - attack.t1098
logsource:
  product: gcp
  service: gcp.audit
detection:
  selection:
    data.protoPayload.authorizationInfo.permission:
      - accesscontextmanager.accessPolicies.delete
      - accesscontextmanager.accessPolicies.accessLevels.delete
      - accesscontextmanager.accessPolicies.accessZones.delete
      - accesscontextmanager.accessPolicies.authorizedOrgsDescs.delete
    data.protoPayload.authorizationInfo.granted: "true"
    data.protoPayload.serviceName: accesscontextmanager.googleapis.com
  condition: selection
falsepositives:
  - Legitimate administrative activities
level: medium
license: DRL-1.1
related:
  - id: 32438676-1dba-4ac7-bf69-b86cba995e05
    type: derived

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