/telegram-bot-security-analysis

name: telegram-bot-security-analysis
description: Reverse engineer and security-test Telegram bots — API analysis, callback interception, exploit discovery, and vulnerability documentation
tags: [telegram, security, reverse-engineering, bot-api, exploit-analysis]
origin: unknown
source_license: see upstream
language: en

Telegram Bot Security Analysis

Comprehensive methodology for analyzing Telegram bots to discover security vulnerabilities, reverse engineer backend systems, and document exploits.

Core Workflow

1. Initial Reconnaissance

**Login and Access:**

from telethon import TelegramClient

API_ID = 94575  # Public Telegram API credentials
API_HASH = 'a3406de8d171bb422bb6ddf3bbd800e2'

client = TelegramClient('session_name', API_ID, API_HASH)
await client.start()

**Bot Information Gathering:**

• Bot ID and access hash
• Available commands
• Button callback data
• Web app URLs
• Inline query support

**Command Discovery:**

commands = [
    '/help', '/menu', '/balance', '/wallet', '/deposit', 
    '/withdraw', '/profile', '/settings', '/admin', '/debug'
]

for cmd in commands:
    await client.send_message(bot, cmd)
    await asyncio.sleep(1)

**Conversation Dump:**

all_msgs = await client.get_messages(bot, limit=200)

conversation = []
for msg in reversed(all_msgs):
    if msg.text:
        sender = "BOT" if msg.from_id == bot.id else "USER"
        conversation.append({
            "sender": sender,
            "time": msg.date.strftime('%Y-%m-%d %H:%M:%S'),
            "text": msg.text,
            "buttons": [[btn.text for btn in row] for row in msg.buttons] if msg.buttons else None
        })

2. Deep API Analysis

**Intercept Callback Data:**

from telethon.tl.functions.messages import GetBotCallbackAnswerRequest

# Get button callback data
for button in msg.reply_markup.rows:
    if hasattr(button, 'data'):
        callback_data = button.data.decode('utf-8', errors='ignore')
        print(f"Callback: {callback_data}")

**Extract Web App URLs:**

# Check for magic links, payment URLs, admin panels
for button in msg.buttons:
    if hasattr(button, 'button') and hasattr(button.button, 'url'):
        url = button.button.url
        if 'magic' in url or 'admin' in url or 'api' in url:
            print(f"Suspicious URL: {url}")

3. Backend Discovery

**Common Patterns:**

• Magic links: `/magic/go/{timestamp}/{user_id}`
• API endpoints: `/api/v1/...`, `/webhook/...`
• Admin panels: `/admin`, `/debug`, `/dashboard`

**Server Fingerprinting:**

curl -I http://target-ip:port/
# Look for: Server header, framework version, error messages

**Endpoint Fuzzing:**

# Common API paths
/api /api/v1 /api/wallet /api/balance /api/deposit
/admin /debug /magic /webhook /callback

4. Exploit Discovery

**Common Vulnerability Classes:**

1. **Premature Reward Distribution**

• Reward given before full verification
• No rollback mechanism
• Missing state validation

2. **2FA/Authentication Bypass**

• Temporary 2FA setup → get reward → disable 2FA
• No continuous verification
• App password validation gaps

3. **Race Conditions**

• Rapid button clicking
• Concurrent requests
• State synchronization issues

4. **Payment Approval Manipulation**

• Webhook triggers on payment approval
• No completion verification
• Abandoned registration still rewards

5. **Referral/Reward Gaming**

• Self-referral loops
• Multiple account exploitation
• Reward duplication

5. Exploit Documentation

**Structure:**

## Vulnerability Summary
- Type: [Premature Reward / Auth Bypass / Race Condition]
- Severity: [Low / Medium / High / Critical]
- Impact: [Financial loss / Data breach / Account takeover]

## Exploit Steps
1. Step-by-step reproduction
2. Required prerequisites
3. Expected outcome

## Technical Details
- Root cause analysis
- Code snippets (if available)
- Attack flow diagram

## Mitigation
- Recommended fixes
- Code patches
- Security best practices

Tools and Techniques

Telethon API Methods

**Message Inspection:**

# Get conversation history
msgs = await client.get_messages(bot, limit=100)

# Filter for specific content
for msg in msgs:
    if msg.buttons:
        # Analyze button structure
    if msg.text and 'reward' in msg.text.lower():
        # Flag reward-related messages

**Callback Testing:**

# Test crafted callback data
test_payloads = [
    b'admin', b'debug', b'wallet', b'claim',
    b'{"action":"deposit","amount":9999}',
]

for payload in test_payloads:
    try:
        result = await client(GetBotCallbackAnswerRequest(
            peer=bot, msg_id=msg.id, data=payload
        ))
        if result.message:
            print(f"Payload {payload} → {result.message}")
    except Exception as e:
        print(f"Payload {payload} → Error: {e}")

Web API Security Testing

For testing backend APIs discovered during bot analysis:

Validation Testing

**Test cases:**

TEST_CASES = [
    # Negative values
    {"amount": -1, "price": 10},
    
    # Zero values
    {"amount": 0, "price": 10},
    
    # Float where integer expected
    {"amount": 0.1, "price": 10},
    
    # Very large numbers (integer overflow)
    {"amount": 2**63, "price": 10},
    
    # SQL injection
    {"amount": "1 OR 1=1", "price": 10},
    {"amount": "1'; DROP TABLE users--", "price": 10},
    
    # XSS injection
    {"amount": "<script>alert(1)</script>", "price": 10},
    
    # Null/undefined
    {"amount": None, "price": 10},
    
    # Type confusion
    {"amount": "1", "price": "10"},  # String instead of number
    {"amount": [1], "price": 10},    # Array instead of number
]

Race Condition Testing

import concurrent.futures

def send_request():
    return requests.post(
        "https://target.com/api/endpoint",
        headers=headers,
        json={"amount": 1, "price": 1