Sim Swap Meaning

A SIM swap is a sophisticated social engineering attack where a malicious actor convinces a mobile carrier to port a victim's phone number to a new SIM card under the attacker's control. By exploiting the human element of carrier customer service, the hacker gains access to all calls and SMS messages intended for the victim.

This is primarily used to intercept SMS-based Two-Factor Authentication (2FA) codes, providing a gateway into bank accounts and crypto exchanges.The technical vulnerability lies in the legacy nature of the "Signaling System No. 7" (SS7) protocol and the reliance on phone numbers as a "Root of Trust." Once the hacker controls the number, they can initiate "Forgot Password" requests across multiple platforms.

Because the SMS code is sent directly to the hacker's device, the victim is often locked out of their accounts before they even realize their phone has lost service.To mitigate this risk, security professionals advocate for moving away from SMS 2FA in favor of Time-based One-Time Passwords (TOTP) like Google Authenticator or hardware security keys like YubiKeys.

In the fintech sector, many apps now implement "SIM Age" checks, which flag accounts if the SIM card associated with the phone number has been changed recently, adding a technical friction layer to prevent the immediate drainage of funds following a swap.