Detections
Analytics

2.10 Ensure That the Log Metric Filter and Alerts Exist for Cloud Storage IAM Permission Changes - alert

Information

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

Rationale:

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.

Impact:

Enabling of logging may result in your project being charged for the additional logs usage.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

From Console:
Create the prescribed log metric:

Go to Logging/Logs-based Metrics by visiting https://console.cloud.google.com/logs/metrics and click 'CREATE METRIC'.

Click the down arrow symbol on the Filter Bar at the rightmost corner and select Convert to Advanced Filter.

Clear any text and add:

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

Click Submit Filter. Display logs appear based on the filter text entered by the user.

In the Metric Editor menu on right, fill out the name field. Set Units to 1 (default) and Type to Counter. This ensures that the log metric counts the number of log entries matching the user's advanced logs query.

Click Create Metric.

Create the prescribed Alert Policy:

Identify the newly created metric under the section User-defined Metrics at https://console.cloud.google.com/logs/metrics.

Click the 3-dot icon in the rightmost column for the new metric and select Create alert from Metric. A new page appears.

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:

Set 'Aggregator' to 'Count'

Set 'Configuration':

- Condition: above

- Threshold: 0

- For: most recent value

Configure the desired notifications channels in the section Notifications.

Name the policy and click Save.

From Command Line:
Create the prescribed Log Metric:

Use the command: gcloud beta logging metrics create

Reference for command usage: https://cloud.google.com/sdk/gcloud/reference/beta/logging/metrics/create

Create the prescribed alert policy:

Use the command: gcloud alpha monitoring policies create

Reference for command usage: https://cloud.google.com/sdk/gcloud/reference/alpha/monitoring/policies/create

See Also

https://workbench.cisecurity.org/files/3817

Item Details

References: CSCv7|6.2, CSCv7|6.3

Plugin: GCP

Control ID: d5a0a7275138b88fa150db1abe39f44322a07f7ba8e63f87828111c7df106419