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When developing custom Telegram Bots using webhooks, your server receives HTTP POST requests from Telegram servers whenever an event occurs. If your webhook endpoint is publicly accessible, attackers can attempt to forge incoming requests unless proper verification is enforced.
The Threat of Unauthenticated Webhook Endpoints
An exposed webhook without header verification allows malicious actors to send fake message payloads to your backend, potentially triggering unauthorized bot actions, database updates, or remote command executions.
Implementing X-Telegram-Bot-Api-Secret-Token
Telegram Bot API supports a security parameter named secret_token when invoking setWebhook. Telegram then includes this string in the X-Telegram-Bot-Api-Secret-Token HTTP header with every request.
Flask Implementation Example
from flask import Flask, request, jsonify, abort
import hmac
app = Flask(__name__)
SECRET_TOKEN = 