id: gcloud-vm-disk-csek-disabled

info:
  name: VM Disk Encryption with Customer-Supplied Keys Disabled
  author: princechaddha
  severity: high
  description: |
    Ensure that the disks attached to your production Google Compute Engine instances are encrypted with Customer-Supplied Encryption Keys (CSEKs) in order to have complete control over the data-at-rest encryption and decryption process, and meet strict compliance requirements.
  impact: |
    Without CSEK encryption, you have limited control over the encryption process of your VM disk data, which may not meet strict compliance requirements for sensitive data protection.
  remediation: |
    Enable Customer-Supplied Encryption Keys (CSEKs) for your VM disks by providing a valid encryption key during disk creation or instance launch. The key must be a 256-bit string encoded in RFC 4648 base64 format.
  reference:
    - https://cloud.google.com/compute/docs/disks/customer-supplied-encryption
  tags: cloud,devops,gcp,gcloud,compute,encryption,csek,security,gcp-cloud-config

flow: |
  code(1)
  for(let projectId of iterate(template.projectIds)){
    set("projectId", projectId)
    code(2)
    for(let instance of iterate(template.instances)){
      instance = JSON.parse(instance)
      set("instanceName", instance.name)
      set("zone", instance.zone)
      code(3)
      for(let disk of iterate(template.disks)){
        set("diskName", disk)
        code(4)
      }
    }
  }

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 instances list --project $projectId --format="json[](name,zone.basename())"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute instances describe $instanceName --zone $zone --project $projectId --format="json(disks[].deviceName)"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute disks describe $diskName --zone $zone --project $projectId --format="json(diskEncryptionKey)" | jq '.sha256 // "null"'

    matchers:
      - type: word
        words:
          - "null"

    extractors:
      - type: dsl
        dsl:
          - '"Disk " + diskName + " attached to instance " + instanceName + " in zone " + zone + " of project " + projectId + " has Customer-Supplied Encryption Keys (CSEKs) disabled"'
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