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I don't fully follow the prefix thing. So a scammer makes a call from a number that's a prefix of my number? That doesn't affect 2FA, that won't show up as "me"
by jakubp 8y ago
I don't fully follow the prefix thing. So a scammer makes a call from a number that's a prefix of my number? That doesn't affect 2FA, that won't show up as "me" on my friends' phone screens when they call, etc... how is that an issue?
- monocasa 8y agoThe scammer is able to forge the signaling and routing. It's not that they have numbers for your prefix, they're just able to connect to SS7, know that they're calling 555-111-2222, and forge the signaling information for say 555-111-3333 hoping that you're more likely to pick up the phone, and you have no way to call them back as they'll not be associated with that number once the call is done. > That doesn't affect 2FA You can use the same techniques to say "I am 555-111-2222, route all sms for that number to me". > that won't show up as "me" on my friends' phone screens when they call They absolutely can do that. It's not that they bought numbers in each of the prefixes, it's that they're forging the signaling information for another number in your prefix dynamically, based on your number.
- jakubp 8y agoThanks :)