T05 · Unauthorized Access and Privilege Escalation
Error
- Location
- roku-telegram.py:32
- Finding
- Telegram callbacks permit unauthorized remote control of the Roku device## Vulnerability Details **File Location**: `roku-telegram.py:32-52` **Vulnerability Type**: Missing sender and chat authorization **Risk Level**: High ### Vulnerable Code ```python url = f"https://api.telegram.org/bot{TOKEN}/getUpdates" params = {"offset": offset, "timeout": 10} if offset else {"timeout": 10} resp = requests.get(url, params=params, timeout=15) data = resp.json() if data.get("ok"): for update in data["result"]: offset = update["update_id"] + 1 if "callback_query" in update: cb = update["callback_query"]["data"] if cb.startswith("roku_"): btn = cb.replace("roku_", "") print(f"→ {btn}", flush=True) send_to_roku(btn) # Answer callback cb_id = update["callback_query"]["id"] requests.post( f"https://api.telegram.org/bot{TOKEN}/answerCallbackQuery", json={"callback_query_id": cb_id} ) ``` ### Technical Analysis The Telegram poller treats every callback whose data starts with `roku_` as an authorized Roku command. It does not verify any of the identity or context fields supplied by Telegram, such as: - `callback_query.from.id` - The originating message's chat ID - Chat type - A configured user or chat allowlist The prefix check is command-format validation, not authorization. Any Telegram account capable of interacting with the configured bot can therefore submit accepted callbacks. The code transmits the callback-query identifier to Telegram's official `answerCallbackQuery` endpoint. This is expected Telegram bot protocol behavior, and the reviewed code does not send local files, Roku data, or unrelated environment variables to another endpoint. However, the bot token is embedded in the request URL and could be exposed by verbose HTTP, proxy, or except ...[truncated 1597 chars]
- Remediation
- ## Remediation Suggestions 1. Require explicit Telegram user and chat allowlists, configured through protected settings: ```python allowed_users = {int(value) for value in os.environ["TELEGRAM_ALLOWED_USERS"].split(",")} allowed_chats = {int(value) for value in os.environ["TELEGRAM_ALLOWED_CHATS"].split(",")} ``` 2. Before processing callback data, require both the sender ID and originating chat ID to match the allowlists. 3. Reject callbacks without an associated message or other expected context. 4. Validate callback data against a fixed command allowlist rather than accepting every `roku_` prefix. 5. Restrict the bot's discoverability and interaction settings where Telegram supports doing so. 6. Do not log full Telegram request URLs because they contain the bot token. 7. Add explicit documentation warning that the Telegram poller creates a remote control channel. 8. Add authorization tests covering unauthorized users, unauthorized chats, malformed updates, and callbacks without messages.