SIM Swapping

What it is

SIM swapping occurs when someone transfers your phone number to a SIM or eSIM under their control without your permission. Related port-out fraud moves the number to another carrier. The attacker can receive future calls and SMS codes, making accounts that rely on the number for recovery vulnerable. It does not automatically copy all data from your physical phone.

How it works

The attacker deceives carrier support, exploits weak account checks, or compromises the carrier account. Once the transfer completes, your phone may lose service while theirs receives messages for your number. They then attempt password resets or other account changes that use SMS as proof of ownership.

How people get tricked

A service outage looks ordinary at first, and the target may not connect it with new security emails. The deception often targets the carrier rather than the phone owner. Personal information collected from breaches can help the attacker pass weak identity checks.

Example scenario

Your phone suddenly loses cellular service while Wi-Fi still works. At the same time, your email receives notices of bank password resets that you did not request.

Warning signs

• Unexpected loss of cellular service when others nearby still have it.
• Carrier notifications about a SIM change or number transfer.
• Unrequested account resets occurring alongside the service loss.

If it happens to you

Contact the carrier immediately from another connection and ask it to investigate and reverse unauthorized transfer. Alert financial providers, secure email and important accounts, and revoke suspicious sessions. Review activity even after service returns because recovering the number does not undo account access.