gcloud-exclude-metadata-from-firewall-logging: Exclude Metadata from Firewall Logging

2025-08-01 gcloud PoC Public

Description

Ensure that Virtual Private Cloud (VPC) firewall logging is not configured to include logging metadata to reduce log file size and optimize cloud storage costs. Including metadata in firewall logs can lead to unnecessary storage costs without significant benefits.

PoC

id: gcloud-exclude-metadata-from-firewall-logging

info:
  name: Exclude Metadata from Firewall Logging
  author: princechaddha
  severity: medium
  description: |
    Ensure that Virtual Private Cloud (VPC) firewall logging is not configured to include logging metadata to reduce log file size and optimize cloud storage costs. Including metadata in firewall logs can lead to unnecessary storage costs without significant benefits.
  impact: |
    Including metadata in firewall logging increases log file sizes, leading to higher storage costs and potential inefficiencies in log analysis.
  remediation: |
    Update the VPC firewall logging configuration to exclude metadata from the logs and reduce storage costs while maintaining logging efficiency.
  reference:
    - https://cloud.google.com/vpc/docs/using-firewall-rules-logging
  tags: cloud,devops,gcp,gcloud,google-cloud-vpc,firewall-logging,security,gcp-cloud-config

flow: |
  code(1)
  for(let projectId of iterate(template.projectIds)){
    set("projectId", projectId)
    code(2)
    for(let network of iterate(template.networks)){
      set("networkName", network)
      code(3)
    }
  }

self-contained: true

code:
  - engine:
      - sh
      - bash
    source: |
      gcloud projects list --format="json(projectId)"

    extractors:
      - type: json
        name: projectIds
        internal: true
        json:
          - '.[].projectId'

  - engine:
      - sh
      - bash
    source: |
      gcloud compute networks list --project $projectId --format="json(name)"

    extractors:
      - type: json
        name: networks
        internal: true
        json:
          - '.[].name'

  - engine:
      - sh
      - bash
    source: |
      gcloud compute firewall-rules list --filter="network=$networkName" --sort-by="priority" --format="json(name,disabled,logConfig)"

    matchers:
      - type: word
        words:
          - "enable': True"
          - "INCLUDE_ALL_METADATA"
        condition: and

    extractors:
      - type: dsl
        dsl:
          - '"The firewall rule in network " + networkName + " in project " + projectId + " has logging metadata set to INCLUDE_ALL_METADATA."'
# digest: 4b0a00483046022100c74b93f6dba2a32c541ab110c7f36c696f2abf584d388faf57831ba0bd8d27ad02210091e2c4b608989e3d533446513f85fcbe95955ac8a51be1754136ee5834473ab6:922c64590222798bb761d5b6d8e72950

# Visit https://trap.biu.life/ to view exploit trends for this vulnerability.

References

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