gcloud-org-auto-iam-grants: Automatic IAM Role Grants for Default Service Accounts Not Disabled

id: gcloud-org-auto-iam-grants

info:
  name: Automatic IAM Role Grants for Default Service Accounts Not Disabled
  author: princechaddha
  severity: medium
  description: |
    Ensure that "Disable Automatic IAM Grants for Default Service Accounts" policy is enforced for your Google Cloud Platform (GCP) organizations and projects in order to deactivate the automatic IAM role grant for default service accounts. When a default service account is created, it is automatically granted the Editor role ("roles/editor") on your project.
  impact: |
    When automatic IAM grants are enabled, default service accounts automatically receive Editor role permissions, which violates the principle of least privilege and increases security risks.
  remediation: |
    Enable the "Disable Automatic IAM Grants for Default Service Accounts" policy at the organization level using the 'gcloud alpha resource-manager org-policies enable-enforce' command or through the Google Cloud Console.
  reference:
    - https://www.trendmicro.com/cloudoneconformity/knowledge-base/gcp/ResourceManager/disable-automatic-role-grants.html
    - https://cloud.google.com/resource-manager/docs/organization-policy/org-policy-constraints
  tags: cloud,devops,gcp,gcloud,resourcemanager,security,iam,organization,gcp-cloud-config

flow: |
  code(1)
  for(let orgId of iterate(template.orgIds)){
    set("orgId", orgId)
    code(2)
  }

self-contained: true

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

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

  - engine:
      - sh
      - bash
    source: |
      gcloud alpha resource-manager org-policies describe iam.automaticIamGrantsForDefaultServiceAccounts --organization=$orgId --effective --format="json(booleanPolicy)"

    matchers:
      - type: word
        words:
          - "{}"

    extractors:
      - type: dsl
        dsl:
          - '"Organization " + orgId + " has not disabled automatic IAM role grants for default service accounts"'
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