Audit Monitor Api Policy Denials Alerts

What this solution is

This architecture centralizes organization-wide Cloud Audit Logs into a dedicated security logging project, establishes custom logs-based metrics targeting specific policy violation streams, and triggers automated alerts via Cloud Monitoring.

How it meets the requirements

• Capturing administrative changes and perimeter denials: Cloud Audit Logs automatically records administrative actions in Admin Activity logs (cloudaudit.googleapis.com%2Factivity) and logs access blocks enforced by perimeter controls (such as VPC Service Controls and IAM) in Policy Denied logs (cloudaudit.googleapis.com%2Fpolicy).
• Automated near-real-time alerting: Creating a user-defined logs-based counter metric on the aggregated Policy Denied log stream extracts counts of denied invocations. Cloud Monitoring evaluates these counts against defined threshold conditions and notifies on-call teams.
• Centralized ingestion: An aggregated log sink defined at the organization root routes logs from all child folders and projects into a centralized log bucket, preventing disparate or dropped project-level auditing.

Key advantages

• Immutability and default coverage: Admin Activity and Policy Denied audit logs are enabled by default and cannot be disabled by project owners, ensuring comprehensive tamper-resistant coverage.
• Granular filter criteria: Logs include caller IP (RequestMetadata.caller_ip), method names (protoPayload.methodName), and resource identities, facilitating precise metric filtering.
• Fast threat detection: Logs-based metrics populate time-series data immediately as log entries are ingested into Cloud Logging.