testland/tenant-leak-test-author
Workflow-driven skill that builds a tenant-leak test plan from an inventory of tenant-bearing surfaces (database tables, APIs, object storage, search indices, async messages) and the isolation model in use. Walks through identifying tenant-bearing surfaces, enumerating the attack patterns per OWASP WSTG-ATHZ-02 (horizontal escalation, vertical escalation, IDOR / BOLA), generating test cases that exercise each pattern against each surface, and emitting the test suite skeleton (pytest / Jest / JUnit / Go test) with explicit cross-tenant probes. Use when designing a multi-tenant test suite for a new feature, when auditing test coverage for an existing tenant boundary, or when reviewing PRs that add tenant-bearing surfaces. Distinct from cross-tenant-data-leak-tests which is the runtime gate; this skill produces the plan.
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framework-skeletons.mdreferences/
Tenant-leak test skeletons
pytest - full horizontal-escalation battery
import pytest
class TestDocumentsTenantIsolation:
"""Per OWASP WSTG-ATHZ-02 - horizontal escalation battery."""
def test_tenant_a_cannot_read_tenant_b_document(
self, client, tenant_a_user, tenant_b_resource
):
# Authenticate as tenant A user
client.force_login(tenant_a_user)
# Attempt to access tenant B's resource by ID
response = client.get(f"/api/documents/{tenant_b_resource.id}/")
assert response.status_code == 404, "Must return 404, not 403, to avoid existence disclosure"
def test_tenant_a_cannot_list_tenant_b_documents(
self, client, tenant_a_user, tenant_b_resource
):
client.force_login(tenant_a_user)
response = client.get("/api/documents/")
assert response.status_code == 200
ids = {d["id"] for d in response.json()["results"]}
assert tenant_b_resource.id not in ids
def test_tenant_id_in_body_is_ignored(
self, client, tenant_a_user, tenant_b
):
client.force_login(tenant_a_user)
# Attempt to create a document for tenant B by spoofing the body
response = client.post(
"/api/documents/",
data={"tenant_id": str(tenant_b.id), "body": "leak"}
)
# Must be rejected (400) or silently scoped to A (201 with A's tenant_id)
if response.status_code == 201:
doc = response.json()
assert doc["tenant_id"] != str(tenant_b.id)
def test_jwt_signed_for_a_rejected_on_b_endpoint(
self, client, tenant_a_user, tenant_b_resource
):
# Sign a JWT for tenant A user, use it on a B-scoped endpoint
token = sign_jwt_for(tenant_a_user)
response = client.get(
f"/api/documents/{tenant_b_resource.id}/",
HTTP_AUTHORIZATION=f"Bearer {token}"
)
assert response.status_code in (401, 404)Postgres RLS-direct (language-agnostic)
For surfaces relying on RLS per row-level-security-postgres-reference,
also test at the DB layer:
-- Connect as app_user (not superuser, not table owner)
BEGIN;
SET LOCAL app.tenant_id = '<tenant_a_uuid>';
-- Insert a row for tenant A
INSERT INTO documents (tenant_id, body) VALUES (current_setting('app.tenant_id')::uuid, 'a-doc');
-- Switch to tenant B
SET LOCAL app.tenant_id = '<tenant_b_uuid>';
SELECT count(*) FROM documents; -- expect 0 (tenant A's row invisible)
-- Cross-tenant INSERT attempt
INSERT INTO documents (tenant_id, body) VALUES ('<tenant_a_uuid>', 'leak');
-- Expect: ERROR: new row violates row-level security policy for table "documents"
ROLLBACK;