SMS OTP are a disaster?

And SMS messages and phone numbers just aren’t that well-defended. A scam called “porting out” or “SIM hijacking” or “SIM swapping” allows crooks to steal your phone number by impersonating you to your phone company to report a lost SIM card and asking them to assign your number to a new one. Criminals use information from public sources and breaches to answer security questions, then they have your number assigned to a phone in their control. From there, it’s easy to seize control of the lion’s share of your accounts.

There’s a thriving underground market for the kinds of accounts that can be stolen this way, from memorable Instagram usernames to Bitcoin exchange accounts.