SIM swapping lets criminals take over your phone number — and with it, every account that uses SMS two-factor authentication. Here's how it works and how to stop it.
SIM swapping is one of the most sophisticated and damaging forms of identity theft targeting consumers today. In a SIM swap attack, a criminal contacts your mobile carrier, impersonates you using personal information gathered from data breaches or social media, and convinces the carrier to transfer your phone number to a SIM card they control. From that moment, every call and text meant for you goes to the attacker.
The immediate target is usually SMS-based two-factor authentication. Once the attacker controls your phone number, they can trigger password resets on your email, bank, and cryptocurrency accounts — receiving the verification codes that are supposed to protect you. High-profile SIM swap victims have lost hundreds of thousands of dollars in cryptocurrency and had their email and social media accounts completely taken over within minutes.
The warning signs of a SIM swap in progress: your phone suddenly loses service and shows 'No Service' or 'SOS Only' even in areas with normal coverage. This is the moment the attacker's SIM has been activated. If this happens, call your carrier immediately from another phone — do not wait.
The most effective defenses: First, add a SIM lock PIN or port freeze to your carrier account — this requires a PIN before any SIM change or number transfer can occur. Every major US carrier offers this. Second, switch from SMS-based 2FA to an authenticator app for all important accounts — authenticator codes are generated on your device and can't be intercepted via SIM swap. Third, use a Google Voice or similar number for SMS 2FA rather than your real mobile number.
If you've been SIM swapped, act immediately: call your carrier to reclaim your number, change passwords on all important accounts from a device that doesn't use your phone number, contact your bank to flag potential fraud, and file reports with the FTC (reportfraud.ftc.gov) and your local FBI field office. SIM swapping is a federal crime under the Computer Fraud and Abuse Act.
Safety 1st Editorial Team
This article is credited to Safety 1st Editorial Team. Safety 1st Consumer Protection has republished this content with attribution.