Ensure That the Log Metric Filter and Alerts Exist for Custom Role Changes

Description:

It is recommended that a metric filter and alarm be established for changes to Identity and Access Management (IAM) role creation, deletion and updating activities.

Rationale:

Google Cloud IAM provides predefined roles that give granular access to specific Google Cloud Platform resources and prevent unwanted access to other resources. However, to cater to organization-specific needs, Cloud IAM also provides the ability to create custom roles. Project owners and administrators with the Organization Role Administrator role or the IAM Role Administrator role can create custom roles.
Monitoring role creation, deletion and updating activities will help in identifying any over-privileged role at early stages.

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

From Console:

Create the prescribed log metric:

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

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

3. Clear any text and add:

resource.type="iam_role"
AND (protoPayload.methodName = "google.iam.admin.v1.CreateRole"
OR protoPayload.methodName="google.iam.admin.v1.DeleteRole"
OR protoPayload.methodName="google.iam.admin.v1.UpdateRole")

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

2. In the 'Metric Editor' menu on the 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 advanced logs query.

3. Click 'Create Metric'.

Create a prescribed Alert Policy:

1. Identify the new metric that was just created under the section 'User-defined Metrics' at https://console.cloud.google.com/logs/metrics.

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

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 ensures 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

1. Configure the desired notification channels in the section 'Notifications'.

2. Name the policy and click 'Save'.

From Google Cloud CLI

Create the prescribed Log Metric:

• Use the command: gcloud logging metrics create

Create the prescribed Alert Policy:

• Use the command: gcloud alpha monitoring policies create