​
Event Information

  1. The dns.policies.delete event in GCP for CloudDNS indicates that a DNS policy has been deleted.
  2. This event signifies that any associated rules and configurations within the DNS policy have been removed.
  3. It is important to monitor this event to ensure that DNS policies are being managed and modified correctly, and to track any changes made to the DNS infrastructure.

​
Examples

  1. Unauthorized deletion of DNS policies: If security is impacted with dns.policies.delete in GCP for CloudDNS, it could potentially allow unauthorized individuals to delete DNS policies. This could lead to disruption of DNS resolution and potentially allow attackers to redirect traffic or perform DNS hijacking.

  2. Loss of DNS configuration: Deleting DNS policies without proper authorization or understanding of the impact can result in the loss of DNS configuration. This can lead to service disruptions, as DNS records may no longer be available, causing websites or applications to become inaccessible.

  3. Impact on DNS-based security controls: DNS policies in GCP CloudDNS are often used to enforce security controls such as DNS-based firewalls or content filtering. Deleting DNS policies without proper planning or coordination can result in the loss of these security controls, potentially exposing the infrastructure to malicious activities or unauthorized access.

​
Remediation

​
Using Console

To remediate the issues mentioned in the previous response for GCP CloudDNS using the GCP console, you can follow these step-by-step instructions:

  1. Enable DNSSEC for GCP CloudDNS:

    • Go to the GCP Console and navigate to the Cloud DNS page.
    • Select the DNS zone for which you want to enable DNSSEC.
    • Click on the “DNSSEC” tab.
    • Click on the “Enable DNSSEC” button.
    • Follow the instructions provided to complete the DNSSEC setup process.

  2. Implement DNS firewall rules for GCP CloudDNS:

    • Go to the GCP Console and navigate to the Cloud DNS page.
    • Select the DNS zone for which you want to implement DNS firewall rules.
    • Click on the “Firewall rules” tab.
    • Click on the “Create a rule” button.
    • Configure the necessary parameters such as source IP ranges, target IP ranges, and action.
    • Click on the “Create” button to create the DNS firewall rule.

  3. Monitor DNS query logs for GCP CloudDNS:

    • Go to the GCP Console and navigate to the Cloud DNS page.
    • Select the DNS zone for which you want to monitor DNS query logs.
    • Click on the “Logs” tab.
    • Enable the “Query logs” toggle switch.
    • Configure the necessary parameters such as log retention period and log sink destination.
    • Click on the “Save” button to start monitoring DNS query logs.

Note: The exact steps may vary slightly depending on the GCP Console interface version and any updates made to the Cloud DNS service. It is always recommended to refer to the official GCP documentation for the most up-to-date instructions.

​
Using CLI

To remediate the issues in GCP CloudDNS using GCP CLI, you can follow these steps:

  1. Ensure proper IAM permissions:

    • Grant the necessary IAM roles to the user or service account executing the CLI commands.
    • Use the gcloud projects add-iam-policy-binding command to add IAM roles to a project.

  2. Implement DNSSEC for CloudDNS:

    • Enable DNSSEC for a managed zone using the gcloud dns managed-zones update command with the --dnssec-state flag set to on.
    • Sign the zone using the gcloud dns dns-keys sign-zone command.

  3. Enable logging and monitoring for CloudDNS:

    • Enable query logging for a managed zone using the gcloud dns managed-zones update command with the --enable-query-logging flag set to true.
    • Create a log sink to export the logs to a desired destination using the gcloud logging sinks create command.
    • Enable monitoring and alerting for CloudDNS using the gcloud alpha monitoring policies create command to create a policy and gcloud alpha monitoring policies update command to update the policy.

Please note that the actual CLI commands may vary based on your specific requirements and configurations.

​
Using Python

To remediate the issues mentioned in the previous response for GCP CloudDNS using Python, you can use the following approaches:

  1. Ensure DNSSEC is enabled:
    • Use the google-cloud-dns Python library to interact with the Cloud DNS API.
    • Use the dnssecConfig method to retrieve the current DNSSEC configuration for a specific managed zone.
    • If DNSSEC is not enabled, use the update method to enable DNSSEC for the managed zone.
from google.cloud import dns

def enable_dnssec(project_id, zone_name):
    client = dns.Client(project=project_id)
    zone = client.zone(zone_name)
    zone.fetch()
    
    if not zone.dnssec_config:
        zone.dnssec_config = dns.DnssecConfig(state=dns.DnssecState.ON)
        zone.update()
        print(f"DNSSEC enabled for zone: {zone_name}")
    else:
        print(f"DNSSEC is already enabled for zone: {zone_name}")
  1. Implement DNS logging:
    • Use the logging Python library to interact with the Cloud Logging API.
    • Create a log sink to export DNS logs to a destination of your choice (e.g., BigQuery, Cloud Storage, Pub/Sub).
    • Configure the log sink to filter DNS-related logs based on specific criteria (e.g., log severity, resource type).
    • Enable the log sink to start exporting DNS logs.
from google.cloud import logging_v2

def create_dns_log_sink(project_id, sink_name, destination_uri, filter_expr):
    client = logging_v2.LoggingServiceV2Client()
    parent = client.project_path(project_id)
    
    sink = {
        "name": sink_name,
        "destination": destination_uri,
        "filter": filter_expr,
        "output_version_format": "V2",
    }
    
    response = client.create_sink(parent, sink)
    print(f"DNS log sink created: {response.name}")
  1. Monitor DNS changes with Cloud Monitoring:
    • Use the google-cloud-monitoring Python library to interact with the Cloud Monitoring API.
    • Create a metric descriptor to define a custom metric for DNS changes.
    • Create a metric time series to record the DNS changes using the custom metric descriptor.
    • Set up an alerting policy to trigger notifications based on specific conditions related to DNS changes.
from google.cloud import monitoring_v3

def create_dns_change_metric(project_id, metric_type, metric_kind, value_type):
    client = monitoring_v3.MetricServiceClient()
    project_name = client.project_path(project_id)
    
    descriptor = {
        "type": metric_type,
        "metric_kind": metric_kind,
        "value_type": value_type,
        "labels": [
            {
                "key": "zone",
                "value_type": "STRING",
                "description": "Managed zone name"
            }
        ]
    }
    
    response = client.create_metric_descriptor(project_name, descriptor)
    print(f"DNS change metric created: {response.name}")

Please note that the provided Python scripts are just examples and may require additional modifications based on your specific requirements and environment setup.