Two critical issues and several high/medium issues were identified during
a security review of the backend API.
**Critical fixes:**
1. Path traversal (CWE-22): user-supplied `simulation_id`, `report_id`,
and `project_id` values were passed directly to `os.path.join()`
without validation, allowing `../` sequences to escape intended
directories.
- Added `backend/app/utils/id_validator.py` with `validate_safe_id()`
(rejects anything that isn't alphanumeric/underscore/hyphen) and
`safe_join()` (resolves realpath and verifies containment).
- Applied to all 3 path-construction sites in simulation.py, all 12
relevant handlers in report.py, and 6 sites in graph.py.
- Sanitized uploaded filenames with `os.path.basename()` in graph.py.
2. Missing authentication: all API endpoints were publicly accessible
with no auth mechanism.
- Added `backend/app/utils/auth.py` with an `X-Api-Key` middleware
registered as a `before_request` hook.
- Auth is opt-in: set `API_KEY` in `.env` to enforce it; if unset a
startup warning is logged. This preserves local dev workflows.
**High fixes:**
3. Hardcoded `SECRET_KEY` fallback replaced with `os.urandom(32).hex()`
so an unset key is never predictable.
4. `FLASK_DEBUG` now defaults to `False` instead of `True`.
5. Full Python tracebacks removed from all API error responses (51 total
across graph.py, report.py, simulation.py) — tracebacks still go to
the logger.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Background threads (graph building, simulation prep, report generation,
profile generation) now inherit the requesting user's locale preference.
Previously these fell back to 'zh' because Flask request context was
unavailable in spawned threads.
- Updated README.md to reflect the removal of the project creation endpoint, adjusting the workflow steps accordingly.
- Removed the `create_project` function from graph.py, streamlining the project management API by eliminating deprecated functionality.
Maggie Chen
ghostubborn
666ghj