🔐 How SIM Swapping Attacks Work

SIM swapping (also called SIM hijacking) is a type of identity theft where an attacker tricks a mobile carrier into transferring your phone number to a SIM card they control. Once they have control of your number, they can intercept SMS messages and phone calls, allowing them to bypass two-factor authentication (2FA) and gain access to your accounts.

🧠 Step-by-Step: How the Attack Works

1. Target Identification

The attacker gathers personal information about the victim. This can include:

Full name

Phone number

Date of birth

Address

Last 4 digits of a Social Security Number (SSN) or ID

Sources:

Social media

Data breaches

Phishing

Public records

2. Social Engineering the Mobile Carrier

The attacker contacts the victim's mobile provider, posing as the victim. They request a SIM swap — often by claiming:

The phone was lost or stolen

A new device needs to be activated

They then convince customer service to:

Deactivate the victim’s current SIM

Activate a new SIM (controlled by the attacker)

3. Takeover of the Phone Number

Once successful:

The victim’s phone loses service

The attacker’s device now receives calls and SMS for that number

This gives the attacker access to:

Two-factor authentication codes

Account recovery links

4. Account Hijacking

With control of the victim’s phone number, the attacker:

Initiates password resets for email, bank, crypto, and social media accounts

Receives the 2FA codes sent via SMS

Gains full access to the victim's accounts

🎯 Common Targets

Crypto investors (access to wallets)

Bank accounts

Email and cloud services

Social media influencers

High-net-worth individuals

🛡️ How to Protect Yourself

Protection Step Why It Helps

Use app-based 2FA (e.g., Google Authenticator) Avoids reliance on SMS

Set up a carrier PIN or password Makes SIM swaps harder

Don’t overshare personal info online Prevents social engineering

Use strong, unique passwords Reduces overall risk

Monitor for SIM activity Unexpected loss of signal can be a red flag

Enable account recovery alternatives Email or hardware tokens (like YubiKey)

🚨 Signs You Might Be a Victim

You suddenly lose phone service (no calls/texts)

You get alerts for account logins or password changes

You can't log into your accounts anymore

🧩 Real-World Examples

High-profile SIM swap attacks have led to:

Theft of millions in cryptocurrency

Hacked Twitter and Instagram accounts

Unauthorized purchases and financial damage

✅ Summary

Term Meaning

SIM Swap Moving your phone number to another SIM card

Goal of Attacker Gain access to SMS-based 2FA and reset accounts

Main Defense Use non-SMS authentication methods and secure your mobile account

Let me know if you want a checklist or a printable version of this guide.

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