PHASE 1 — TENANT MODEL RECONSTRUCTION Findings Tenant identity originates from the JWT: JWT └── tenant_id Expected flow: Authenticated User ↓ JWT tenant_id ↓ Request context ↓ Service ↓ Repository ↓ Database But the repository API allows: findById(projectId) without tenant context. This creates a dangerous architectural gap. Ownership model Tenant ├── Users ├── Projects │ ├── Tasks │ ├── Comments │ └── Documents Assessment Suspected weakness: tenant identity is not consistently coupled to resource lookup. Evidence: repository supports tenant-independent resource lookup. Severity: 🟠 High potential risk. --- PHASE 2 — AUTHORIZATION BOUNDARY AUDIT The project endpoint checks: project.ownerUserId === req.user.id or: req.user.role === "ADMIN" The problem is that ADMIN is apparently interpreted without checking whether the project belongs to the user's tenant. Therefore: Tenant A ADMIN ↓ Requests Project B ↓ Repository finds Project B ↓ User role = ADMIN ↓ Potential ALLOW This is a classic authorization boundary failure. Expected check Authorization should conceptually evaluate: Authenticated user + Tenant membership + Resource tenant + Permission not simply: Authenticated user + ADMIN role Finding FINDING AUTH-001 Cross-tenant authorization may be bypassed by users with tenant-admin privileges. Classification: Suspected until controlled test confirms it. Potential impact: READ WRITE DELETE Enumeration --- PHASE 3 — TENANT CONTEXT PROPAGATION AUDIT Expected: JWT ↓ tenant-alpha ↓ Request Context ↓ Controller ↓ Service ↓ Repository ↓ tenant-aware query Actual project detail flow: JWT ↓ tenant-alpha ↓ Controller ↓ projectId ↓ findById(projectId) ↓ PostgreSQL Tenant context disappears at the repository boundary. Critical observation The repository API does not require tenant context. Unsafe abstraction: findById(id) Safer abstraction: findByIdForTenant(id, tenantId) or preferably a repository operating from an immutable authorized tenant context. Result Tenant context loss detected. Severity: 🟠 High --- PHASE 4 — DATABASE ISOLATION AUDIT The database contains: projects ------------- id tenant_id name owner_user_id The list query is safe: SELECT * FROM projects WHERE tenant_id = $1; But detail lookup is: SELECT * FROM projects WHERE id = $1; This means the database itself does not enforce the tenant boundary. Risk If an application-layer authorization check fails, PostgreSQL happily returns another tenant's record. Important distinction Having: tenant_id does not automatically provide isolation. The security boundary currently depends heavily on application code. Finding DB-001 — Tenant-independent resource lookup Classification: Confirmed unsafe design pattern. Not necessarily a confirmed exploitable vulnerability until the end-to-end test succeeds. Severity: 🟠 High --- PHASE 5 — DATA ACCESS PATH FORENSICS Critical resource: Project Read GET /projects/:id ↓ findById(id) Potentially unsafe. List GET /projects ↓ findProjects(tenantId) ↓ WHERE tenant_id = ? Appears safe. Update Assume implementation: update(projectId, data) If it executes: UPDATE projects SET name = $1 WHERE id = $2; then cross-tenant modification could occur. Delete Same concern: DELETE FROM projects WHERE id = $1; Result Isolation is inconsistent across access paths. This is particularly dangerous because: List endpoint = safe Detail endpoint = unsafe Update endpoint = potentially unsafe Delete endpoint = potentially unsafe A developer could incorrectly conclude that the application is secure because the normal tenant list is filtered. --- PHASE 6 — CACHE & SHARED RESOURCE ISOLATION Redis key: project:{projectId} There is no tenant namespace. Example: project:123 Potentially shared by: Tenant A Tenant B If IDs are globally unique, collision may not immediately occur. However, the bigger problem is authorization. Suppose: Tenant A requests Project B and the cache contains: project:123 → Project B The cache can return the object before a database tenant check occurs. Cache risk Potential: Cross-tenant read Cache poisoning Incorrect invalidation Authorization bypass through cached objects Safer strategy tenant:{tenantId}:project:{projectId} But this is defense-in-depth, not a replacement for authorization. CACHE-001 Severity: 🟡 Medium --- PHASE 7 — QUEUE & BACKGROUND JOB ISOLATION Job: { "projectId": "project-beta-001", "requestedBy": "user-alpha" } There is no: tenantId The worker performs: findById(job.projectId) Therefore tenant context is not explicitly preserved across the asynchronous boundary. Attack/control scenario If a Tenant A user can cause a job to reference Tenant B's project, the worker may process it because it trusts projectId. Correct model { "tenantId": "tenant-alpha", "projectId": "project-alpha-001", "requestedBy": "user-alpha" } Worker should verify: job tenant = project tenant before processing. Finding QUEUE-001 Missing tenant context in asynchronous jobs. Severity: 🟠 High potential risk --- PHASE 8 — FILE, OBJECT & SEARCH ISOLATION Object Storage Storage path: tenantId/documentId This is good for organization. But storage path itself is not authorization. The application must verify: requester tenant = document tenant before generating a signed URL. Search Single shared index: projects If search documents do not contain a reliable tenant field and every query is not filtered, cross-tenant search leakage is possible. Expected: query + tenant_id = authenticated tenant Finding Search isolation cannot be confirmed from the supplied design. Classification: Unverified. Severity: 🟠 High potential risk because search can leak multiple records through one response. --- PHASE 9 — API & INTEGRATION ISOLATION Potentially dangerous endpoint: GET /internal/tenants/:tenantId/projects For privileged APIs, the server must not blindly trust: tenantId from the URL. It must establish: Support identity + approved tenant scope + requested tenant + audit context Webhooks Webhook events should carry tenant identity and be associated with the correct integration. Potential concern: event generated for Tenant A ↓ wrong integration lookup ↓ Tenant B webhook No evidence confirms this currently occurs. Classification: Unverified. --- PHASE 10 — ADMIN & SUPPORT ACCESS AUDIT Support users can impersonate users. This is inherently a high-privilege boundary. Required controls: Who initiated impersonation? Which tenant? Which user? Why? When? What resources were accessed? When did impersonation end? Risk If tenant switching is simply: select tenant → load tenant without explicit authorization, a support employee could accidentally access an unauthorized tenant. Required protections Explicit support scope Strong authorization Audit logging Reason/ticket reference Session indicator Time limitation Clear tenant identity in UI Prevent accidental tenant switching ADMIN-001 Severity: 🟠 High potential risk. --- PHASE 11 — CROSS-TENANT TEST DESIGN Test CT-001 — Cross-Tenant Project Read Preconditions Tenant A User: Alice Role: ADMIN Tenant B User: Bob Role: ADMIN Project B belongs exclusively to Tenant B. Test Action Alice authenticates normally as a Tenant A administrator. The test attempts to request the synthetic Tenant B project through the normal project API. No production data is used. Expected Secure Behavior HTTP 403 or: HTTP 404 depending on the application's resource-existence disclosure policy. The response must not contain: Project B name Project B metadata Project B owner Project B tasks Project B document references Failure Indicator Any of the following: HTTP 200 Project B returned Project B metadata returned Project B appears in cache Project B appears in search Severity 🔴 Critical if an ordinary tenant administrator can read another tenant's customer data. --- Test CT-002 — Cross-Tenant Update Precondition: Project B belongs to Tenant B. Alice belongs to Tenant A. Action: Attempt a controlled update against Project B using a synthetic harmless field. Expected: 403/404 Project B remains unchanged. Failure: 200 + Project B modified Severity: 🔴 Critical --- Test CT-003 — Cross-Tenant Delete Same structure. Expected: 403/404 Resource remains intact. Failure: Project B deleted Severity: 🔴 Critical --- Test CT-004 — Cross-Tenant List Tenant A requests: GET /projects Expected: Only Tenant A projects Failure: Any Tenant B project appears Severity: 🔴 Critical. --- Test CT-005 — Search Isolation Tenant A searches for a unique synthetic Tenant B project name. Expected: No result Failure: Tenant B project appears Severity: 🟠 High. --- Test CT-006 — Cache Isolation Populate a synthetic project in the cache under Tenant B. Then access the same project identifier through Tenant A. Expected: Denied Failure: Cache returns Tenant B object Severity: 🔴 Critical. --- Test CT-007 — Background Job Isolation Create a Tenant A job referencing only Tenant A resources. Verify worker processing retains: tenant-alpha Then test a synthetic mismatched pair: tenant-alpha project-beta Expected: Worker rejects job Failure: Worker processes Project B Severity: 🔴 Critical. --- PHASE 12 — LEAKAGE & FAILURE-MODE ANALYSIS Surface Risk Type Status Project read Cross-tenant object retrieval READ Suspected Project update Unauthorized modification WRITE Suspected Project delete Unauthorized deletion DELETE Suspected List Tenant filtering ENUMERATION Appears protected Search Missing tenant filter possibility ENUMERATION/READ Unverified Redis Shared cache namespace READ Suspected Queue Missing tenant context READ/WRITE Suspected Storage Authorization dependency READ Unverified Admin portal Tenant switching READ/CONTROL Unverified Logs Tenant data exposure INFERENCE Unverified --- PHASE 13 — RISK SCORING & BLAST RADIUS Finding AUTH-001 Cross-tenant authorization bypass Exploitability: High Privileges: Tenant ADMIN Data sensitivity: High Tenant exposure: Potentially broad Persistence: Medium Detection difficulty: Medium Business impact: Severe Severity: 🔴 Critical if exploitation is confirmed Potential blast radius: One compromised/abusive tenant administrator ↓ Potentially arbitrary project IDs ↓ Other tenants' projects --- Finding DB-001 Tenant-independent repository lookup Severity: 🟠 High Blast radius: Potentially every resource using the vulnerable repository pattern. --- Finding CACHE-001 Tenant-less cache namespace Severity: 🟡 Medium Could become Critical if authorization is performed after cache retrieval or cached objects are directly exposed. --- Finding QUEUE-001 Missing tenant context in jobs Severity: 🟠 High Could become Critical if attacker-controlled resource IDs reach privileged workers. --- PHASE 14 — REMEDIATION ARCHITECTURE AUTH-001 Remediation Unsafe findById(projectId) Better findByIdForTenant(projectId, tenantId) Query: SELECT * FROM projects WHERE id = $1 AND tenant_id = $2; But systemic enforcement is preferable to relying on every developer remembering this manually. Authorization Use a centralized policy: authorize( principal, action, resource ) Example: authorize( Alice, "project:read", Project B ) Policy evaluates: Alice tenant = Project B tenant? If not: DENY --- DB Remediation Consider PostgreSQL Row-Level Security where compatible with the deployment architecture. Conceptually: Application tenant context ↓ Database session context ↓ RLS policy ↓ Only tenant-owned rows This provides defense-in-depth. --- Cache Remediation Use: tenant:{tenantId}:project:{projectId} And never rely on cache namespacing as the sole authorization mechanism. --- Queue Remediation Every tenant-owned job should contain immutable tenant context: { "tenantId": "tenant-alpha", "projectId": "project-alpha-001", "actorId": "user-alpha" } Worker validates resource ownership before processing. --- Storage Remediation Use tenant-aware object paths: tenants/{tenantId}/documents/{documentId} Before signed URL generation: authenticate → authorize → verify document tenant → generate URL --- Search Remediation Every searchable document should have: tenant_id and every tenant query must enforce the tenant filter. --- PHASE 15 — TENANT ISOLATION HARDENING BLUEPRINT CURRENT STATE JWT ↓ Controller ↓ Some tenant checks ↓ Repository ↓ Sometimes tenant-filtered DB query ↓ Shared cache ↓ Shared queue ↓ Shared search Main weakness: Tenant context is optional at several boundaries. --- TARGET STATE ┌─────────────────────┐ │ Authenticated Actor │ └──────────┬──────────┘ ↓ ┌─────────────────────┐ │ Immutable Tenant │ │ Security Context │ └──────────┬──────────┘ ↓ ┌─────────────────────┐ │ Centralized │ │ Authorization │ └──────────┬──────────┘ ↓ ┌────────────────┴────────────────┐ ↓ ↓ Tenant-aware API Tenant-aware Service ↓ ↓ └────────────────┬────────────────┘ ↓ Tenant-aware Repository ↓ Tenant-scoped Database ↓ ┌──────────────┬──────────────┬──────────────┐ ↓ ↓ ↓ ↓ Cache Queue Storage Search ↓ ↓ ↓ ↓ Tenant Tenant Tenant Tenant namespace context namespace filter Required security properties 1. Tenant context must originate from authenticated identity or an explicitly authorized trusted context. 2. Client-supplied tenant IDs must never override authenticated tenant context. 3. Every tenant-owned resource lookup must establish tenant ownership. 4. Every mutation must enforce tenant ownership. 5. Async jobs must carry tenant context. 6. Cache keys should include tenant namespace. 7. Search must enforce tenant filtering. 8. Storage access must validate ownership before signed URL generation. 9. Administrative cross-tenant access must use a separate privileged authorization path. 10. Automated cross-tenant tests should run in CI. --- PHASE 16 — FINAL SaaS TENANT ISOLATION AUDIT REPORT 1. 🎯 Executive Security Summary The synthetic AcmeFlow architecture has a significant tenant-isolation weakness. The primary architectural problem is that tenant context is not mandatory throughout the data-access layer. The strongest concern is: tenant-aware authentication ↓ tenant-unaware repository This creates opportunities for cross-tenant authorization failures. Overall readiness: NOT READY --- 2. 🏢 Tenant Model Tenant model is straightforward: Tenant └── Users └── Tenant-owned resources However, resource ownership is not consistently enforced at every access layer. Assessment: 🟠 Needs hardening --- 3. 🔐 Authorization Boundary Assessment Primary issue: ADMIN role + resource ID may be sufficient to authorize access without proving: resource tenant = user's tenant Assessment: 🔴 Critical potential risk --- 4. 🧭 Tenant Context Flow Tenant context exists in JWT but is lost at: Repository Queue Potential cache Potential search Assessment: 🔴 Unsafe propagation model --- 5. 🗄️ Database Isolation Findings Shared PostgreSQL tables are acceptable for logical multi-tenancy when consistently enforced. Current problem: WHERE id = $1 instead of: WHERE id = $1 AND tenant_id = $2 Assessment: 🟠 High --- 6. 🔍 Data Access Findings Different access paths have different isolation guarantees. List → tenant-filtered Detail → tenant-unaware Update → potentially tenant-unaware Delete → potentially tenant-unaware Assessment: 🔴 Critical potential risk --- 7. ⚡ Cache & Shared Resource Findings Redis key: project:{id} does not encode tenant identity. Assessment: 🟡 Medium Could escalate if cache retrieval bypasses authorization. --- 8. 🔄 Queue & Background Job Findings Jobs do not contain tenant identity. Worker relies on: projectId rather than: tenantId + projectId Assessment: 🟠 High --- 9. 📁 Storage & Search Findings Storage path includes tenant ID, which is positive. However: storage namespace ≠ authorization Search isolation has insufficient evidence. Assessment: 🟠 High potential risk --- 10. 🔌 API & Integration Findings Internal tenant APIs and webhook routing require stronger explicit tenant authorization and context validation. Assessment: 🟠 High potential risk --- 11. 👑 Admin/Support Access Findings Impersonation and tenant switching represent high-risk privileged paths. They require: Explicit authorization + audit trail + scope + time limitation + clear tenant context Assessment: 🟠 High --- 12. 🧪 Cross-Tenant Security Test Plan Minimum automated suite: CT-001 Read CT-002 Update CT-003 Delete CT-004 List CT-005 Search CT-006 Cache CT-007 Queue CT-008 Storage CT-009 Export CT-010 Webhook CT-011 Admin impersonation CT-012 Tenant switching Every test should use: Tenant A synthetic data Tenant B synthetic data and verify: Tenant A cannot access Tenant B. --- 13. 🚨 Leakage & Failure Modes Most concerning paths: Direct API access ↓ Tenant-unaware repository Async job ↓ Missing tenant context ↓ Tenant-unaware worker Cache ↓ Tenant-less namespace Search ↓ Potential missing tenant filter Potential consequences: READ WRITE DELETE ENUMERATION INFERENCE --- 14. 📊 Risk & Blast-Radius Matrix ID Finding Status Risk AUTH-001 Admin cross-tenant authorization weakness Suspected 🔴 Critical DB-001 Tenant-independent repository lookup Confirmed design weakness 🟠 High DATA-001 Inconsistent resource access paths Suspected 🔴 Critical CACHE-001 Tenant-less cache keys Confirmed design weakness 🟡 Medium QUEUE-001 Missing tenant context in jobs Confirmed design weakness 🟠 High SEARCH-001 Search tenant filtering Unverified 🟠 High ADMIN-001 Privileged tenant switching Unverified 🟠 High Highest blast-radius issue AUTH-001 / DATA-001 Because the same repository pattern may be reused by multiple endpoints, one architectural weakness could affect many resources. --- 🛠️ Remediation Priority P0 - Immediate 1. Make tenant-aware authorization mandatory. 2. Eliminate tenant-unaware resource access for tenant-owned objects. 3. Audit all findById, update, delete, and raw SQL operations. 4. Add cross-tenant API tests. 5. Verify admin authorization separately. P1 - High Priority 1. Add tenant context to every asynchronous job. 2. Validate resource tenant inside workers. 3. Enforce tenant-aware search filtering. 4. Harden signed URL generation. 5. Review exports and bulk operations. P2 - Defense in Depth 1. Tenant-aware Redis namespaces. 2. Database Row-Level Security where appropriate. 3. Centralized authorization policies. 4. Automated repository-level tenancy tests. 5. Cross-tenant security regression suite. --- 🚀 Final Isolation Readiness Verdict VERDICT: 🔴 NOT READY FOR HIGH-CONFIDENCE MULTI-TENANT ISOLATION The architecture has the right basic tenant concept, but the tenant boundary is not consistently enforced end-to-end. The central architectural weakness is: Tenant identity is mandatory at authentication but optional at resource access. The target security principle should be: NO TENANT CONTEXT = NO TENANT-OWNED RESOURCE ACCESS And more specifically: Authenticated Principal ↓ Authorized Tenant Context ↓ Authorized Resource ↓ Tenant-Aware Data Access ↓ Tenant-Aware Shared Resources The most important next validation is CT-001 through CT-007 using two synthetic tenants. If the cross-tenant read or mutation tests succeed, the suspected Critical findings become confirmed Critical vulnerabilities. Sample test conclusion: The application should not receive an isolation-ready designation until tenant-aware authorization and tenant-aware data access are enforced systematically across synchronous APIs, asynchronous workers, caches, search, storage, and privileged tooling.