GHSA-gph2-j4c9-vhhr WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks
SummaryThe YPTSocket plugin's WebSocket server relays attacker-supplied JSON message bodies to every connected client without sanitizing the `msg` or `callback` fields. On the client side, `plugin/YPTSocket/script.js` contains two `eval()` sinks fed directly by those relayed fields (`json.msg.autoEvalCodeOnHTML` at line 568 and `json.callback` at line 95). Because tokens are minted for anonymous visitors and never revalidated beyond decryption, an unauthenticated attacker can broadcast arbitrary JavaScript that executes in the origin of every currently-connected user (including administrators), resulting in universal account takeover, session theft, and privileged action execution.DetailsToken issuance is unauthenticated`plugin/YPTSocket/getWebSocket.json.php:11-21` returns a token to anyone whose request reaches the endpoint — the only check is that the plugin is enabled:`getEncryptedInfo()` in `plugin/YPTSocket/functions.php:3-16` populates `from_users_id = User::getId()` (0 for guests) and `isAdmin = User::isAdmin()` (false for guests). The issued token is accepted by the WebSocket server's `onOpen` handler (`Message.php:44-52`) solely by successful decryption — there is no requirement for the connecting principal to be authenticated.Server relays attacker JSON verbatim`plugin/YPTSocket/Message.php:191-245` — the default branch of `onMessage` only rewrites `from_identification`:`msgToResourceId()` at `Message.php:297-310` copies the attacker-controlled `callback` and `msg` fields into the outbound payload:`$obj` is JSON-encoded at line 335 and sent to every connected client.Client-side sink #1: `autoEvalCodeOnHTML` → eval`plugin/YPTSocket/script.js:163-169` (raw WebSocket transport) sets every inbound frame as `yptSocketResponse` and unconditionally calls `parseSocketResponse()`:`parseSocketResponse()` at `script.js:545-569` reaches the sink:Client-side sink #2: `json.callback` → eval`plugin/YPTSocket/script.js:91-95` — `processSocketJson()` concatenates attacker-controlled `json.callback` into an eval'd string. This path is reachable on BOTH transports: the raw WebSocket branch (`script.js:182`) and the Socket.IO branch (`script.js:339` via `socket.on("message", (data) => { … processSocketJson(data) })`):Because `json.callback` is interpolated as raw source, a payload like `alert(document.cookie);window.x` breaks out of the `typeof` expression and executes during the condition evaluation.PoCPrerequisite: target is running AVideo with the YPTSocket plugin enabled (default on most installs).**Step 1 — obtain a token anonymously** (no cookies, no auth):Expected output (abbreviated):**Step 2 — connect to the WebSocket endpoint** using the returned `webSocketURL`. A minimal Node.js client:**Step 3 — observe impact.** Every other user currently connected to the same AVideo instance (via any page that loads YPTSocket's `script.js` — the global footer, the admin dashboard, live streams, video pages) receives the broadcast. In their browser:Payload 1 reaches `parseSocketResponse()` at line 568 and evaluates `eval(json.msg.autoEvalCodeOnHTML)`, firing the exfiltration request to `attacker.example` with `document.cookie`.Payload 2 reaches `processSocketJson()` at line 95; the synthesized `code` string is `if (typeof alert(document.domain);window.x == 'function') { ... }`, which executes `alert(document.domain)` during the `typeof` evaluation.Any administrator who is online at the moment of the broadcast has their session cookie exfiltrated and/or arbitrary actions performed in their browser context.ImpactA single unauthenticated request and one WebSocket frame grants the attacker **universal client-side code execution** across every user currently connected to the target AVideo instance. Concretely:Session theft of every connected user, including administrators (note: `HttpOnly` does not help because the attacker's JS runs in-origin and can call privileged endpoints directly without ever reading cookies).Privileged action execution on behalf of any admin who happens to be online — including plugin installation (`GHSA-v8jw-8w5p-23g3` shows admin plugin ZIP upload is already an RCE primitive), user promotion/demotion, video deletion, configuration changes.Stored cross-user JS persistence via `localStorage`, IndexedDB, or re-submitting the payload as a comment/title through admin credentials.Financial redirection (payment flows, crypto-donation addresses) and phishing via arbitrary DOM rewriting of the authentic AVideo origin.The scope change (S:C) is genuine: an unauthenticated (or low-privileged) attacker's actions cross the trust boundary into every other user's browser authorization context, including admin.Recommended FixMultiple defense-in-depth layers are required:**1. Remove the client-side eval sinks entirely.** `plugin/YPTSocket/script.js`:No legitimate server flow should push arbitrary JavaScript through a broadcast channel — if server-driven UI updates are needed, use structured data and predefined handler functions.Replace the callback dispatch at lines 91-95 with a strict name-based lookup against a predefined allowlist:**2. Server-side: allowlist keys on relayed `msg` objects.** In `plugin/YPTSocket/Message.php::onMessage()` default branch, whitelist the fields permitted in relayed broadcasts rather than forwarding `$msg['msg']` verbatim:**3. Restrict token issuance and sender privileges.** `plugin/YPTSocket/getWebSocket.json.php` should require authentication (or at least reject anonymous broadcast capability). Unprivileged senders should not be permitted to trigger `msgToAll` at all — the default branch of `onMessage` should require `$msgObj->isAdmin` (or equivalent) before allowing broadcasts, since there is no legitimate reason for arbitrary clients to originate system-wide messages.
CVSS v3.1 score: 10