Publicly Accessible Google Cloud KMS Keys

ID: gcloud-kms-public-access

Severity: high

Author: princechaddha

Tags: cloud,devops,gcp,gcloud,google-kms,gcp-cloud-config

Description

Ensure that the IAM policy associated with your Google Cloud Key Management Service (KMS) keys restricts anonymous and/or public access. The KMS cryptographic keys are controlled by Cloud IAM policies, which should not include bindings for “allUsers” and “allAuthenticatedUsers” to prevent public internet access.

YAML Source

id: gcloud-kms-public-access

info:
  name: Publicly Accessible Google Cloud KMS Keys
  author: princechaddha
  severity: high
  description: |
    Ensure that the IAM policy associated with your Google Cloud Key Management Service (KMS) keys restricts anonymous and/or public access. The KMS cryptographic keys are controlled by Cloud IAM policies, which should not include bindings for "allUsers" and "allAuthenticatedUsers" to prevent public internet access.
  impact: |
    If a KMS key is accessible to "allUsers" or "allAuthenticatedUsers", it means any internet user can access this cryptographic resource, potentially leading to unauthorized data access or manipulation.
  remediation: |
    Update the IAM policy for your KMS keys by removing any bindings that include "allUsers" or "allAuthenticatedUsers" to restrict access to authenticated and authorized users only.
  reference:
    - https://cloud.google.com/kms/docs/restricting-access
  tags: cloud,devops,gcp,gcloud,google-kms,gcp-cloud-config

flow: |
  code(1)
  for(let keyRing of iterate(template.keyRings)){
    set("keyRing", keyRing)
    code(2)
    for(let key of iterate(template.keys)){
      set("keyName", key)
      code(3)
    }
  }

self-contained: true

code:
  - engine:
      - sh
      - bash
    source: |
      gcloud kms keyrings list --location=global --format="json(name)"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud kms keys list --keyring=$keyRing --location=global --format="json(name)"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud kms keys get-iam-policy $keyName --keyring=$keyRing --location=global --format="json"

    matchers:
      - type: word
        words:
          - "allUsers"
          - "allAuthenticatedUsers"
        condition: or

    extractors:
      - type: dsl
        dsl:
          - '"Public Access found in KMS Key: " + keyName + ", KeyRing: " + keyRing + ", Location: Global"'
# digest: 4a0a0047304502200402be881c65a286a9279a473cd5998ed03b59d7bc7b293fbcc7f066d97086a2022100890f44b29b1aa33d0c86d0403639c36d6da4fb6aa427a2fe9f26af3e6f42ef34:922c64590222798bb761d5b6d8e72950

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/kms/gcloud-kms-public-access.yaml"

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