Control: 2.10 Ensure that the log metric filter and alerts exist for Cloud Storage IAM permission changes

Description

It is recommended that a metric filter and alarm be established for Cloud Storage Bucket IAM changes.

Monitoring changes to cloud storage bucket permissions may reduce the time needed to detect and correct permissions on sensitive cloud storage buckets and objects inside the bucket.

Remediation

From Console

Create a required log metric:

1. Login to GCP console and navigate to Logs-based Metrics.
2. Click CREATE METRIC.
3. Select Metric Type as Counter, enter Log metric name and Units to 1.
4. Clear any text in the Build filter field and add below text

resource.type=gcs_bucket
AND protoPayload.methodName="storage.setIamPermissions"

5. Click CREATE METRIC. The logs display based on the filter text entered by the user.

Create a required alert policy for the log metric::

1. Identify the newly created metric under the section User-defined Metrics.
2. Click the 3-dot icon in the right most column for the desired metric and select Create alert from metric. A new page opens.
3. Fill out the alert policy configuration and click Save. Choose the alerting threshold and configuration that makes sense for the user's organization. For example, a threshold of zero(0) for the most recent value will ensure that a notification is triggered for every owner change in the project.
4. Configure the desired notifications channels in the section Notifications.
5. Enter Alert name and click Save.

From Command Line

Create a required log metric:

• Use the command: gcloud beta logging metrics create.
• Reference for Command Usage.

Create a alert policy for the log metric:

• Use the command: gcloud alpha monitoring policies create.
• Reference for Command Usage.