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Description

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

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 meet 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 updates helps identify over-privileged roles early.

Impact​

Enabling logging may result in your project being charged for additional log usage.

Audit​

From Google Cloud Console​

Ensure that the prescribed log metric is present:

  1. Go to Logging/Logs-based Metrics by visiting https://console.cloud.google.com/logs/metrics.

  2. In the User-defined Metrics section, ensure that at least one metric {{log-metric-name}} is present with filter text:

    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")

Ensure that the prescribed alerting policy is present:

  1. Go to Alerting by visiting https://console.cloud.google.com/monitoring/alerting.
  2. Under the Policies section, ensure that at least one alert policy exists for the log metric above. Clicking on the policy should show that it is configured with a condition. For example, Violates when: Any logging.googleapis.com/user/<Log Metric Name> stream is above a threshold of zero(0) for greater than zero(0) seconds means that the alert will trigger for any new owner change. Verify that the chosen alerting thresholds make sense for the user's organization.
  3. Ensure that the appropriate notifications channels have been set up.

From Google Cloud CLI​

Ensure that the prescribed log metric is present:

  1. List the log metrics:

    gcloud logging metrics list \
        --format=json

  2. Ensure that the output contains at least one metric with the filter set to:

    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")

  3. Note the value of the property metricDescriptor.type for the identified metric, in the format logging.googleapis.com/user/<Log Metric Name>.

Ensure that the prescribed alerting policy is present:

  1. List the alerting policies:

    gcloud alpha monitoring policies list \
        --format=json

  2. Ensure that the output contains at least one alert policy where:

    • conditions.conditionThreshold.filter is set to metric.type=\"logging.googleapis.com/user/<Log Metric Name>\"

    • AND enabled is set to true.

References​

  1. https://cloud.google.com/logging/docs/logs-based-metrics/
  2. https://cloud.google.com/monitoring/custom-metrics/
  3. https://cloud.google.com/monitoring/alerts/
  4. https://cloud.google.com/logging/docs/reference/tools/gcloud-logging
  5. https://cloud.google.com/iam/docs/understanding-custom-roles