Unconfigured Cloud CDN Origin Authentication

ID: gcloud-cdn-origin-auth-unconfigured

Severity: medium

Author: princechaddha

Tags: cloud,devops,gcp,gcloud,cloud-cdn,gcp-cloud-config

Description

Ensure that Cloud CDN origins are configured to authenticate access to the content available at backend (backend buckets or backend services) using signed cookies and signed URLs. Signed cookies and URLs are designed to prevent unauthorized users from bypassing the authentication process and accessing sensitive information.

YAML Source

id: gcloud-cdn-origin-auth-unconfigured

info:
  name: Unconfigured Cloud CDN Origin Authentication
  author: princechaddha
  severity: medium
  description: |
    Ensure that Cloud CDN origins are configured to authenticate access to the content available at backend (backend buckets or backend services) using signed cookies and signed URLs. Signed cookies and URLs are designed to prevent unauthorized users from bypassing the authentication process and accessing sensitive information.
  impact: |
    If Cloud CDN origins are not properly configured with signed cookies and signed URLs, it could lead to unauthorized access and potential exposure of sensitive information. This configuration is essential for maintaining the security and integrity of content delivery.
  remediation: |
    Configure your Cloud CDN origins to use signed cookies and URLs by adding signed request keys to your backend services. This will enforce authentication on CDN-cached content, preventing unauthorized access.
  reference:
    - https://cloud.google.com/cdn/docs/using-signed-urls
  tags: cloud,devops,gcp,gcloud,cloud-cdn,gcp-cloud-config

flow: |
  code(1)
  for(let projectId of iterate(template.projectIds)){
    set("projectId", projectId)
    code(2)
    for(let backendService of iterate(template.backendServices)){
      set("backendServiceName", backendService)
      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 backend-services list --global --project $projectId --format="json(name,enableCDN)"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute backend-services describe $backendServiceName --global --format="json(cdnPolicy.signedUrlKeyNames)"

    matchers:
      - type: word
        words:
          - 'null'

    extractors:
      - type: dsl
        dsl:
          - '"Unconfigured Cloud CDN Origin Authentication: " + backendServiceName + " in Project: " + projectId'
# digest: 4a0a00473045022019bda07807eb922316b8d39af34b048276477aa10516e5f33bdd63513d0283ab022100add40bcc817cd9335b7b92320421beb717427a50977069b0b7411e8ae3afdd8b:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

$ nuclei -u "URL" -t "cloud/gcp/cdn/gcloud-cdn-origin-auth-unconfigured.yaml"

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