SIM Swap Attacks: Complete Guide to Account Takeover 
> Posted by: sim_swapper | Rank: Senior Member | Joined: 2023 [/I]
This guide covers SIM swap attack vectors for defensive research.
SIM swapping is one of the most effective account takeover methods.
By porting a victim's phone number to your SIM, you can bypass SMS-based 2FA and take over accounts. Here's the complete breakdown.
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━━━ RECON PHASE ━━━[/B]
Information Gathering:
Code:
# Phone number format analysis
+1 (555) 123-4567 = US format
+44 7911 123456 = UK format
# Carrier lookup
• IMEI.info - Device info by IMEI
• SIMswap.pro - Carrier identification
• Carrier lookup databases
# Social engineering targets
• Victim's carrier (check through support chats)
• Carrier employee contacts
• Store locations near victim---
━━━ SIM SWAP METHODS ━━━
Method 1: Social Engineering Carrier Support
Code:
Script:
"Hi, I'm having issues with my phone. I lost it yesterday
and need to transfer my number to a new SIM. Can you help
me with the verification?"
Required Info:
• Full name (matching carrier records)
• Account PIN/password
• Last 4 of SSN
• Date of birth
• Address on file
Red Flags to Avoid:
• Don't ask for too much info at once
• Don't sound like you're reading from a script
• Have a plausible story readyMethod 2: Store Visit (Insider-Assisted)
Code:
# Find carrier store locations
• Google Maps search
• Carrier store locators
# What you need:
• Government ID (fake or borrowed)
• Knowledge of account details
• Cash for SIM cost ($10-20)
# Process:
1. Visit store with ID matching victim's name
2. Request SIM replacement
3. Provide account verification info
4. Get new SIM with victim's numberMethod 3: Port-Out Attack
Code:
# Some carriers allow number porting to new carriers
# This is harder but more reliable
# Requirements:
• Account number from carrier
• PIN or PUK code
• Billing info verification
# Carriers with weaker porting security:
• Regional/Prepaid carriers
• Smaller MVNOs
• International carriers---
━━━ ACCOUNT TAKEOVER FLOW ━━━
Code:
Phase 1: SIM Swap Complete
├── Victim loses SMS/call reception
├── Your device receives all SMS/calls
└── Carrier confirms port complete
Phase 2: Account Discovery
├── Search email for SMS-based 2FA services
├── Check common platforms:
│ • Gmail/Google Accounts
│ • Facebook
│ • Twitter/X
│ • Instagram
│ • PayPal
│ • Crypto exchanges
│ • Banking apps
└── Document all targets
Phase 3: Password Reset Abuse
├── Use "Forgot Password" on each service
├── Reset to new email you control
├── Bypass SMS 2FA (you have the number)
└── Access account
Phase 4: Account Control
├── Change recovery email
├── Disable 2FA
├── Add your own 2FA methods
└── Monitor for victim detection---
━━━ DEFENSE MEASURES ━━━
How to Protect Yourself:
Code:
1. Use Authenticator Apps
• Google Authenticator
• Authy
• 1Password
• NOT SMS-based 2FA
2. Set Carrier PINs
• AT&T: Account PIN
• Verizon: Security PIN
• T-Mobile: Passcode
• Prevents unauthorized SIM swaps
3. Enable App-Based 2FA
• Hardware keys (YubiKey)
• TOTP apps
• WebAuthn
4. Monitor Your Number
• Watch for unexpected SMS about SIM changes
• Check carrier app for port status
• Report suspicious activity immediately
5. Use Email-Based Recovery
• Set email as primary recovery
• Disable SMS recovery where possible---
━━━ TOOLS & SCRIPTS ━━━
Carrier Lookup Script:
Code:
#!/usr/bin/env python3
"""
Carrier Lookup & SIM Swap Recon Tool
"""
import requests
import json
import re
class SIMRecon:
def __init__(self):
self.carrier_db = self.load_carriers()
def load_carriers(self):
"""Load carrier database"""
return {
"us": {
"major": ["AT&T", "Verizon", "T-Mobile", "Sprint"],
"prepaid": ["Metro", "Boost", "Cricket", "Straight Talk"],
"mvno": ["Google Fi", "Visible", "Mint", "US Mobile"]
},
"uk": {
"major": ["EE", "O2", "Vodafone", "Three"],
"prepaid": ["giffgaff", "Lyca", "Tesco Mobile"]
}
}
def lookup_carrier(self, phone_number):
"""Determine carrier from phone number"""
# Extract country code
if phone_number.startswith('+1'):
country = 'us'
number = phone_number[2:]
elif phone_number.startswith('+44'):
country = 'uk'
number = phone_number[3:]
else:
return {"error": "Unsupported country code"}
# Carrier lookup by prefix
prefixes = {
"us": {
"201": "Verizon", "202": "AT&T", "203": "T-Mobile",
"212": "Verizon", "213": "AT&T", "214": "T-Mobile",
"215": "Verizon", "216": "AT&T", "217": "T-Mobile",
}
}
prefix = number[:3]
carrier = prefixes.get(country, {}).get(prefix, "Unknown")
return {
"phone": phone_number,
"country": country,
"carrier": carrier,
"prepaid": carrier in ["Metro", "Boost", "Cricket"]
}
def check_sms_2fa_risk(self, email):
"""Check if email likely uses SMS 2FA"""
risk_services = []
# Common services that use SMS 2FA
services = [
"gmail.com", "facebook.com", "twitter.com",
"instagram.com", "paypal.com", "coinbase.com",
"binance.com", "kraken.com"
]
for service in services:
if service in email:
risk_services.append(service)
return {
"email": email,
"risk_level": "high" if len(risk_services) > 3 else "medium",
"services_at_risk": risk_services
}
if __name__ == "__main__":
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--phone', help='Phone number to lookup')
parser.add_argument('--email', help='Email to check 2FA risk')
args = parser.parse_args()
recon = SIMRecon()
if args.phone:
result = recon.lookup_carrier(args.phone)
print(json.dumps(result, indent=2))
if args.email:
result = recon.check_sms_2fa_risk(args.email)
print(json.dumps(result, indent=2))---
━━━ LEGAL & ETHICAL CONSIDERATIONS ━━━
Code:
⚠️ IMPORTANT:
• SIM swapping without authorization is ILLEGAL
• Penalties include felony charges and imprisonment
• This guide is for EDUCATIONAL purposes only
• Always obtain written authorization before testing
• Report vulnerabilities responsibly---
━━━ TL;DR ━━━
Code:
✅ SIM swaps exploit weak carrier security
✅ Social engineering is the primary vector
✅ SMS 2FA is NOT secure
✅ Use authenticator apps instead
✅ Set carrier PINs to prevent swaps---
Questions? Drop 'em below.
Next: Checkout automation techniques.
Last edited by sim_swapper; 1 hour ago.
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sim_swapper | Senior Member | Account Takeover Specialist
"The phone is the new security key" ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━[/SIG][/b][/b][/b][/b][/b][/b]