| name | cis-gcp-foundations-2.7 |
| description | Ensure That the Log Metric Filter and Alerts Exist for VPC Network Firewall Rule Changes |
| category | cis-gcp-foundations |
| version | 4.0.0 |
| author | cyberstrike-official |
| tags | ["cis","gcp","logging","monitoring","log-metrics","alerts","vpc","firewall"] |
| cis_id | 2.7 |
| cis_benchmark | CIS Google Cloud Platform Foundation Benchmark v4.0.0 |
| tech_stack | ["gcp"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
Ensure That the Log Metric Filter and Alerts Exist for VPC Network Firewall Rule Changes (Automated)
Description
It is recommended that a metric filter and alarm be established for Virtual Private Cloud (VPC) Network Firewall rule changes.
Rationale
Monitoring for Create or Update Firewall rule events gives insight to network access changes and may reduce the time it takes to detect suspicious activity.
Impact
Enabling of logging may result in your project being charged for the additional logs usage. These charges could be significant depending on the size of the organization.
Audit Procedure
Using Google Cloud Console
Ensure that the prescribed log metric is present:
- Go to
Logging/Logs-based Metrics by visiting https://console.cloud.google.com/logs/metrics.
- In the
User-defined Metrics section, ensure that at least one metric <Log_Metric_Name> is present with this filter text:
resource.type="gce_firewall_rule"
AND (protoPayload.methodName:"compute.firewalls.patch"
OR protoPayload.methodName:"compute.firewalls.insert"
OR protoPayload.methodName:"compute.firewalls.delete")
Ensure that the prescribed alerting policy is present:
- Go to
Alerting by visiting https://console.cloud.google.com/monitoring/alerting.
- 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.
- Ensure that appropriate notification channels have been set up.
Using Google Cloud CLI
Ensure that the prescribed log metric is present:
- List the log metrics:
gcloud logging metrics list --format json
- Ensure that the output contains at least one metric with the filter set to:
resource.type="gce_firewall_rule"
AND (protoPayload.methodName:"compute.firewalls.patch"
OR protoPayload.methodName:"compute.firewalls.insert"
OR protoPayload.methodName:"compute.firewalls.delete")
