Exfiltration: BigQuery Data Exfiltration

This document describes a threat finding type in Security Command Center. Threat findings are generated by threat detectors when they detect a potential threat in your cloud resources. For a full list of available threat findings, see Threat findings index.

Overview

Findings that are returned by the Exfiltration: BigQuery Data Exfiltration contain one of two possible subrules. Each subrule has a different severity:

  • Subrule exfil_to_external_table with severity = HIGH:
    • A resource was saved outside of your organization or project.
  • Subrule vpc_perimeter_violation with severity = LOW:
    • VPC Service Controls blocked a copy operation or an attempt to access BigQuery resources.

How to respond

To respond to this finding, do the following:

Step 1: Review finding details

  1. Open the Exfiltration: BigQuery Data Exfiltration finding, as directed in Reviewing findings.

  2. On the Summary tab of the finding details panel, review the listed values in the following sections:

    • What was detected:
      • Severity: the severity is either HIGH for subrule exfil_to_external_table or LOW for subrule vpc_perimeter_violation.
      • Principal email: the account used to exfiltrate the data.
      • Exfiltration sources: details about the tables from which data was exfiltrated.
      • Exfiltration targets: details about the tables where exfiltrated data was stored.
    • Affected resource:
      • Resource full name: the full resource name of the project, folder, or organization from which data was exfiltrated.
    • Related links:
      • Cloud Logging URI: link to Logging entries.
      • MITRE ATT&CK method: link to the MITRE ATT&CK documentation.
      • Related findings: links to any related findings.

  3. Click the Source Properties tab and review the fields shown, especially:

    • detectionCategory:
      • subRuleName: either exfil_to_external_table or vpc_perimeter_violation.
    • evidence:
      • sourceLogId:
        • projectId: the Google Cloud project that contains the source BigQuery dataset.
    • properties
      • dataExfiltrationAttempt
        • jobLink: the link to the BigQuery job that exfiltrated data.
        • query: the SQL query run on the BigQuery dataset.

  4. Optionally, click the JSON tab for the complete listing of the JSON properties of the finding.

Step 2: Review permissions and settings

  1. In the Google Cloud console, go to the IAM page.

    Go to IAM

  2. If necessary, select the project listed in the projectId field in the finding JSON.

  3. On the page that appears, in the Filter box, enter the email address listed in Principal email and check what permissions are assigned to the account.

Step 3: Check logs

  1. On the Summary tab of the finding details panel, click the Cloud Logging URI link to open the Logs Explorer.

  2. Find admin activity logs related to BigQuery jobs by using the following filters:

    • protoPayload.methodName="Jobservice.insert"
    • protoPayload.methodName="google.cloud.bigquery.v2.JobService.InsertJob"

Step 4: Research attack and response methods

  1. Review the MITRE ATT&CK framework entry for this finding type: Exfiltration Over Web Service: Exfiltration to Cloud Storage.
  2. Review related findings by clicking the link on the Related findings on the Related findings row in the Summary tab of the finding details. Related findings are the same finding type on the same instance and network.
  3. To develop a response plan, combine your investigation results with MITRE research.

Step 5: Implement your response

The following response plan might be appropriate for this finding, but might also impact operations. Carefully evaluate the information you gather in your investigation to determine the best way to resolve findings.

What's next