GCP Audit Logs - Detect Organization Policy Deletion or Updation

id: 205e1c9f-faee-43f1-b3b8-1952ffbbeea4
name: GCP Audit Logs - Detect Organization Policy Deletion or Updation
description: |
  'Detects when a Google Cloud Platform organization policy is deleted or updated. 
  Organization policies provide centralized control over your organization's cloud resources and help ensure security and compliance.
  Deletion or modification of org policies may indicate an attempt to bypass security controls or weaken the security posture of GCP projects.
  Adversaries may delete or update organization policies to disable security constraints before performing malicious activities.'
severity: High
status: Available
requiredDataConnectors:
  - connectorId: GCPAuditLogsDefinition
    dataTypes:
      - GCPAuditLogs
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1562.001
tags:
  - GCP
  - IAM Organization Policy
  - Compliance
query: |
  GCPAuditLogs
  | where ServiceName == "orgpolicy.googleapis.com"
  | where MethodName has_any ("OrgPolicy.DeletePolicy", "OrgPolicy.UpdatePolicy")
  | extend 
      RequestMetadataJson = parse_json(RequestMetadata),
      AuthInfoJson = parse_json(AuthenticationInfo),
      AuthzInfoJson = parse_json(AuthorizationInfo)
  | extend 
      PolicyName = split(GCPResourceName, "/")[-1],
      CallerIpAddress = tostring(RequestMetadataJson.callerIp),
      UserAgent = tostring(RequestMetadataJson.callerSuppliedUserAgent),
      AuthEmail = tostring(AuthInfoJson.principalEmail),
      Permission = tostring(AuthzInfoJson[0].permission),
      PermissionGranted = tostring(AuthzInfoJson[0].granted)
  | extend 
      AccountName = tostring(split(PrincipalEmail, "@")[0]), 
      AccountUPNSuffix = tostring(split(PrincipalEmail, "@")[1])
  | project TimeGenerated,
            PrincipalEmail,
            AuthEmail,
            ProjectId,
            ResourceName = GCPResourceName,
            PolicyName,
            CallerIpAddress,
            UserAgent,
            MethodName,
            ServiceName,
            Severity,
            Permission,
            PermissionGranted,
            LogName,
            InsertId,
            AccountName,
            AccountUPNSuffix
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: PrincipalEmail
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: CallerIpAddress
  - entityType: CloudApplication
    fieldMappings:
      - identifier: Name
        columnName: ProjectId
      - identifier: InstanceName
        columnName: ResourceName
customDetails:
  ProjectId: ProjectId
  PolicyName: PolicyName
  ResourceName: ResourceName
  UserAgent: UserAgent
  Permission: Permission
  MethodName: MethodName
alertDetailsOverride:
  alertDisplayNameFormat: "GCP Organization Policy {{PolicyName}} Deleted by {{PrincipalEmail}}"
  alertDescriptionFormat: |-
    Organization policy {{PolicyName}} was deleted. This action may weaken security controls and compliance posture.
    
    Resource: {{ResourceName}}
    Source IP: {{CallerIpAddress}}
    
    Investigate whether this deletion was authorized and assess the impact on security controls.
version: 1.0.1
kind: Scheduled