# SIM Swap

> An attack where a scammer takes over your phone number to bypass two-factor authentication and break into accounts.

Canonical URL: https://fudfomo.co/glossary/sim-swap
Source: What The Block! Dictionary v1.0 (last updated 2026-04-25), browsable at https://wtb.fudfomo.co.

## Definition

A SIM swap attack happens when a scammer convinces a mobile carrier to transfer your phone number to a SIM card they control. Once they have the number, they can intercept SMS-based two-factor codes and reset passwords on email and exchange accounts.

Crypto holders are a frequent target. The standard defences are using app-based or hardware two-factor authentication, locking your number with the carrier, and never relying on SMS for important accounts.

## Related terms

- [Phishing](https://fudfomo.co/glossary/phishing): A scam where attackers impersonate a trusted service to steal credentials or trick you into signing a bad transaction.
- [Custody](https://fudfomo.co/glossary/custody): Who holds your crypto and the keys to it. Self-custody means you do, custodial means a company does.
- [CEX](https://fudfomo.co/glossary/cex): A centralised exchange. A regulated platform where you buy and sell crypto using an account.

## See the full catalogue

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