Square’s scary and impressive identity confirmation screen (zaidfarooqui.com)

Banks, credit card companies know a lot about you - residences, employment history, family history etc.

All the data is tied to your SSN.

If you've ever done a credit report, you'll recognize these questions; these sorts of questions are standard fare.

I suspect it's not Square doing them, but rather, they're just farming identity verification out to another vendor who already does this sort of thing.

I'm fairly certain that they are using 3rd party service to run these checks. It's a well-established industry with banks, credit unions, car dealerships, etc as their clients.