CRITICAL SECURITY FIX: Implemented Defense in Depth security pattern by adding
explicit TenantId verification to all Epic/Story/Task Query and Command Handlers.
Security Impact:
- BEFORE: Relied solely on EF Core global query filters (single layer)
- AFTER: Explicit TenantId validation + EF Core filters (defense in depth)
This ensures that even if EF Core query filters are accidentally disabled or bypassed,
tenant isolation is still maintained at the application layer.
Changes:
Query Handlers (6 handlers):
- GetEpicByIdQueryHandler: Added ITenantContext injection + explicit TenantId check
- GetStoryByIdQueryHandler: Added ITenantContext injection + explicit TenantId check
- GetTaskByIdQueryHandler: Added ITenantContext injection + explicit TenantId check
- GetEpicsByProjectIdQueryHandler: Verify Project.TenantId before querying Epics
- GetStoriesByEpicIdQueryHandler: Verify Epic.TenantId before querying Stories
- GetTasksByStoryIdQueryHandler: Verify Story.TenantId before querying Tasks
Command Handlers (5 handlers):
- UpdateEpicCommandHandler: Verify Project.TenantId before updating
- UpdateStoryCommandHandler: Verify Project.TenantId before updating
- UpdateTaskCommandHandler: Verify Project.TenantId before updating
- DeleteStoryCommandHandler: Verify Project.TenantId before deleting
- DeleteTaskCommandHandler: Verify Project.TenantId before deleting
Unit Tests:
- Updated 5 unit test files to mock ITenantContext
- All 32 unit tests passing
- All 7 multi-tenant isolation integration tests passing
Defense Layers (Security in Depth):
Layer 1: EF Core global query filters (database level)
Layer 2: Application-layer explicit TenantId validation (handler level)
Layer 3: Integration tests verifying tenant isolation (test level)
Test Results:
- Unit Tests: 32/32 PASSING
- Integration Tests: 7/7 PASSING (multi-tenant isolation)
This fix addresses a critical security vulnerability where we relied on a single
layer of defense (EF Core query filters) for tenant data isolation. Now we have
multiple layers ensuring no cross-tenant data leaks can occur.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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