SIM Swap

A type of fraud where an attacker convinces a mobile operator to transfer a victim's phone number to a new SIM card under the attacker's control. Once successful, the attacker receives all calls and SMS messages intended for the victim, enabling bypass of SMS-based two-factor authentication, account takeover, and financial fraud.

Categories: Radio Access NetworkIdentity and SubscriberSecurity Controls

SIM Swap in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

Subscriber identifiers (IMSI, SUPI, MSISDN, IMEI) anchor authentication, charging and lawful interception. Any protocol that leaks a permanent identifier is treated as a privacy defect, which is why 5G introduced SUCI concealment on the air interface.

To place SIM Swap in the wider telecom-security picture, review 2G, Authentication, IMSI Catcher (Cell Site Simulator), OTA, USIM and WCDMA — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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