gcloud-ssl-policy-insecure-ciphers: Insecure SSL Cipher Suites in GCP Load Balancers

id: gcloud-ssl-policy-insecure-ciphers

info:
  name: Insecure SSL Cipher Suites in GCP Load Balancers
  author: princechaddha
  severity: medium
  description: |
    This check scans SSL policies of Google Cloud HTTPS and SSL Proxy load balancers to identify insecure cipher suites. It ensures SSL policies use TLS 1.2 with secure profiles and exclude weak ciphers.
  impact: |
    Insecure cipher suites can lead to vulnerabilities, allowing attackers to decrypt or intercept data.
  remediation: |
    Ensure SSL policies use MODERN or RESTRICTED profiles, or a secure CUSTOM profile without weak ciphers.
  reference:
    - https://cloud.google.com/load-balancing/docs/ssl-policies
  tags: cloud,devops,gcp,gcloud,google-cloud-load-balancing,gcp-cloud-config

flow: |
  code(1)
  for(let projectId of iterate(template.projectIds)){
    set("projectId", projectId)
    code(2)
    for(let proxy of iterate(template.httpsProxies)){
      set("sslPolicy", proxy.sslPolicy)
      code(4)
    }
    code(3)
    for(let proxy of iterate(template.sslProxies)){
      set("sslPolicy", proxy.sslPolicy)
      code(4)
    }
  }

self-contained: true

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

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute target-https-proxies list --project $projectId --format="json(name,sslPolicy)"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute target-ssl-proxies list --project $projectId --format="json(name,sslPolicy)"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute ssl-policies describe $sslPolicy --format="json(minTlsVersion,profile,enabledFeatures)"

    matchers:
      - type: word
        words:
          - 'TLS_1_0'
          - 'TLS_RSA_WITH_AES_128_GCM_SHA256'
          - 'TLS_RSA_WITH_AES_256_GCM_SHA384'
          - 'TLS_RSA_WITH_AES_128_CBC_SHA'
          - 'TLS_RSA_WITH_AES_256_CBC_SHA'
          - 'TLS_RSA_WITH_3DES_EDE_CBC_SHA'

      - type: dsl
        dsl:
          - '"Insecure SSL Policy Detected in Proxy: " + sslPolicy + " in Project: " + projectId'
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