Django Access Control & IDOR Review

Find access control vulnerabilities by investigating how the codebase answers one question:

Can User A access, modify, or delete User B's data?

When to Use

• You need to review Django or DRF code for access control gaps, IDOR risk, or object-level authorization failures.
• The task involves confirming whether one user can access, modify, or delete another user's data.
• You want an investigation-driven authorization review instead of generic pattern matching.

Philosophy: Investigation Over Pattern Matching

Do NOT scan for predefined vulnerable patterns. Instead:

1. Understand how authorization works in THIS codebase
2. Ask questions about specific data flows
3. Trace code to find where (or if) access checks happen
4. Report only what you've confirmed through investigation

Every codebase implements authorization differently. Your job is to understand this specific implementation, then find gaps.

Phase 1: Understand the Authorization Model

Before looking for bugs, answer these questions about the codebase:

How is authorization enforced?

Research the codebase to find:

□ Where are permission checks implemented?
  - Decorators? (@login_required, @permission_required, custom?)
  - Middleware? (TenantMiddleware, AuthorizationMiddleware?)
  - Base classes? (BaseAPIView, TenantScopedViewSet?)
  - Permission classes? (DRF permission_classes?)
  - Custom mixins? (OwnershipMixin, TenantMixin?)

□ How are queries scoped?
  - Custom managers? (TenantManager, UserScopedManager?)
  - get_queryset() overrides?
  - Middleware that sets query context?

□ What's the ownership model?
  - Single user ownership? (document.owner_id)
  - Organization/tenant ownership? (document.organization_id)
  - Hierarchical? (org -> team -> user -> resource)
  - Role-based within context? (org admin vs member)

Investigation commands

# Find how auth is typically done
grep -rn "permission_classes\|@login_required\|@permission_required" --include="*.py" | head -20

# Find base classes that views inherit from
grep -rn "class Base.*View\|class.*Mixin.*:" --include="*.py" | head -20

# Find custom managers
grep -rn "class.*Manager\|def get_queryset" --include="*.py" | head -20

# Find ownership fields on models
grep -rn "owner\|user_id\|organization\|tenant" --include="models.py" | head -30

Do not proceed until you understand the authorization model.

Phase 2: Map the Attack Surface

Identify endpoints that handle user-specific data:

What resources exist?

□ What models contain user data?
□ Which have ownership fields (owner_id, user_id, organization_id)?
□ Which are accessed via ID in URLs or request bodies?

What operations are exposed?

For each resource, map:

• List endpoints - what data is returned?
• Detail/retrieve endpoints - how is the object fetched?
• Create endpoints - who sets the owner?
• Update endpoints - can users modify others' data?
• Delete endpoints - can users delete others' data?
• Custom actions - what do they access?

Phase 3: Ask Questions and Investigate

For each endpoint that handles user data, ask:

The Core Question

"If I'm User A and I know the ID of User B's resource, can I access it?"

Trace the code to answer this:

1. Where does the resource ID enter the system?
   - URL path: /api/documents/{id}/
   - Query param: ?document_id=123
   - Request body: {"document_id": 123}

2. Where is that ID used to fetch data?
   - Find the ORM query or database call

3. Between (1) and (2), what checks exist?
   - Is the query scoped to current user?
   - Is there an explicit ownership check?
   - Is there a permission check on the object?
   - Does a base class or mixin enforce access?

4. If you can't find a check, is there one you missed?
   - Check parent classes
   - Check middleware
   - Check managers
   - Check decorators at URL level

Follow-Up Questions

□ For list endpoints: Does the query filter to user's data, or return everything?

□ For create endpoints: Who sets the owner - the server or the request?

□ For bulk operations: Are they scoped to user's data?

□ For related resources: If I can access a document, can I access its comments?
  What if the document belongs to someone else?


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