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Event Information

  1. The google.pubsub.v1.Subscriber.DetachSubscription event in GCP for Pubsub indicates that a subscription has been detached from a subscriber.
  2. This event is triggered when a subscriber no longer wants to receive messages from a specific subscription.
  3. It is important to monitor this event as it can help track changes in subscription ownership or identify any issues with message delivery.

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Examples

  1. Unauthorized access: If security is impacted with google.pubsub.v1.Subscriber.DetachSubscription in GCP Pub/Sub, it could potentially allow unauthorized users to detach subscriptions from topics. This could lead to data leakage or disruption of critical business processes if sensitive information is exposed or if important messages are not received by intended recipients.

  2. Data integrity: Detaching a subscription from a topic without proper authorization could result in data integrity issues. If an attacker gains access to detach subscriptions, they could potentially modify or delete messages, leading to data corruption or loss. This could have serious implications for applications relying on the consistency and accuracy of the data being exchanged through Pub/Sub.

  3. Service availability: If security is compromised with google.pubsub.v1.Subscriber.DetachSubscription, an attacker could potentially detach subscriptions from critical topics, causing service disruptions or denial of service for legitimate users. This could impact the availability of applications relying on Pub/Sub for real-time messaging and event-driven architectures, leading to financial losses or reputational damage for organizations.

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Remediation

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Using Console

  1. Enable audit logging for GCP Pub/Sub:

    • Go to the GCP Console and navigate to the Pub/Sub section.
    • Select the specific Pub/Sub topic or subscription that you want to enable audit logging for.
    • Click on the “Edit” button to modify the settings.
    • Under the “Logging” section, enable the “Audit logs” option.
    • Choose the appropriate log sink destination, such as Cloud Storage or BigQuery.
    • Save the changes.

  2. Implement VPC Service Controls for GCP Pub/Sub:

    • Go to the GCP Console and navigate to the VPC Service Controls section.
    • Create a new service perimeter or select an existing one that includes the Pub/Sub resources.
    • Configure the access levels and permissions for the Pub/Sub resources within the service perimeter.
    • Apply the service perimeter to the appropriate projects or organizations.
    • Save the changes.

  3. Implement IAM roles and permissions for GCP Pub/Sub:

    • Go to the GCP Console and navigate to the IAM & Admin section.
    • Select the specific project that contains the Pub/Sub resources.
    • Click on the “IAM” tab to manage IAM roles and permissions.
    • Assign the appropriate IAM roles to the users or service accounts that need access to Pub/Sub.
    • Make sure to follow the principle of least privilege and only grant the necessary permissions.
    • Save the changes.

Note: These instructions assume that you have the necessary permissions and access to the GCP Console.

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Using CLI

To remediate the issues mentioned in the previous response for GCP Pub/Sub using GCP CLI, you can follow these steps:

  1. Enable audit logging for Pub/Sub:

    • Use the following command to enable audit logging for Pub/Sub: 
      gcloud pubsub topics set-iam-policy <TOPIC_NAME> policy.json
    • Replace <TOPIC_NAME> with the name of the Pub/Sub topic you want to enable audit logging for.
    • Create a policy.json file with the following content: 
      {
  "auditConfigs": [
    {
      "auditLogConfigs": [
        {
          "logType": "DATA_READ",
          "exemptedMembers": []
        },
        {
          "logType": "DATA_WRITE",
          "exemptedMembers": []
        }
      ],
      "service": "pubsub.googleapis.com"
    }
  ],
  "bindings": [
    {
      "role": "roles/pubsub.publisher",
      "members": [
        "user:<USER_EMAIL>"
      ]
    }
  ]
}
    • Replace <USER_EMAIL> with the email address of the user who should have the pubsub.publisher role.

  2. Implement VPC Service Controls for Pub/Sub:

    • Use the following command to create a VPC Service Controls perimeter for Pub/Sub: 
      gcloud access-context-manager perimeters create <PERIMETER_NAME> --resources=pubsub.googleapis.com/projects/<PROJECT_ID>/locations/-/topics/*
    • Replace <PERIMETER_NAME> with a name for the perimeter and <PROJECT_ID> with your GCP project ID.

  3. Enable Pub/Sub encryption at rest:

    • Use the following command to enable encryption at rest for Pub/Sub: 
      gcloud pubsub topics update <TOPIC_NAME> --message-storage-policy-encryption-key=projects/<PROJECT_ID>/locations/global/keyRings/<KEY_RING_NAME>/cryptoKeys/<CRYPTO_KEY_NAME>
    • Replace <TOPIC_NAME> with the name of the Pub/Sub topic you want to enable encryption for, <PROJECT_ID> with your GCP project ID, <KEY_RING_NAME> with the name of the key ring, and <CRYPTO_KEY_NAME> with the name of the crypto key.

Please note that the above commands assume you have the necessary permissions to perform these actions in your GCP project.

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Using Python

To remediate the issues mentioned in the previous response for GCP Pub/Sub using Python, you can follow these steps:

  1. Enable VPC Service Controls:

    • Use the google-cloud-securitycenter library to enable VPC Service Controls for your project.
    • Here’s an example Python script to enable VPC Service Controls:
    from google.cloud import securitycenter

client = securitycenter.SecurityCenterClient()

# Set the project ID and organization ID
project_id = 'your-project-id'
organization_id = 'your-organization-id'

# Enable VPC Service Controls
response = client.update_organization_settings(
    organization_settings={
        'name': f'organizations/{organization_id}/organizationSettings',
        'enable_vpc_service_controls': True
    }
)

print('VPC Service Controls enabled successfully.')

  2. Implement Pub/Sub access controls:

    • Use the google-cloud-pubsub library to implement access controls for your Pub/Sub topics and subscriptions.
    • Here’s an example Python script to create a new topic with access controls:
    from google.cloud import pubsub_v1

publisher = pubsub_v1.PublisherClient()

# Set the project ID and topic name
project_id = 'your-project-id'
topic_name = 'your-topic-name'

# Create a new topic with access controls
topic_path = publisher.topic_path(project_id, topic_name)
topic = publisher.create_topic(request={"name": topic_path, "labels": {"access_level": "private"}})

print(f'Topic {topic.name} created successfully with access controls.')

  3. Monitor and analyze Pub/Sub logs:

    • Use the google-cloud-logging library to monitor and analyze the logs generated by Pub/Sub.
    • Here’s an example Python script to retrieve and analyze Pub/Sub logs:
    from google.cloud import logging

client = logging.Client()

# Set the project ID and filter for Pub/Sub logs
project_id = 'your-project-id'
filter_str = 'logName:"projects/{project_id}/logs/cloudaudit.googleapis.com%2Fdata_access"'

# Retrieve and analyze Pub/Sub logs
logs = client.list_entries(filter_=filter_str)
for log in logs:
    print(f'Log entry: {log.payload}')

Please note that you need to install the required libraries (google-cloud-securitycenter, google-cloud-pubsub, google-cloud-logging) using pip before running these scripts.