tl;dr > The use of phone numbers as both lock and key has led to the rise, in recent years, of so-called SIM swapping attacks, in which an attacker steals your

tl;dr > The use of phone numbers as both lock and key has led to the rise, in recent years, of so-called SIM swapping attacks, in which an attacker steals your phone number. When you add two-factor authentication to an account and receive your codes through SMS texts, they go to the attacker instead, along with any calls and texts intended for the victim. Sometimes attackers even use inside sources at carriers who will transfer numbers for them.