How Hackers Are Hijacking Your Cellphone Account
They simply intercept the one-time verification code
Fraudsters have figured out how to break in to online accounts protected by two-factor authentication, where the authenticating device is your mobile phone.
They don’t steal the phone; they simply hijack the phone number. This enables them to intercept those one-time verification codes sent to that mobile number by text, email, or phone call.
Armed with their victim’s personal information, such as date of birth and last four digits of their Social Security number — information that is widely available on the dark web — these identity thieves trick the wireless carriers into transferring (or porting) their target’s phone number to a new account or device they control. That’s why this is called the “port-out” scam.
Please select this link to read the complete article from NBC News.