Question about i.d. theft?

Question

What's to stop someone from building a program to check every possible combination of numbers, check them all on Paypal and other sites, and then return a report?
.

Since the viloator's answer will probably be removed, I just want everyone to know what she said. "Hey you pathetic crazy clown lady with the retard son...yes! We did use her ID for Y!A and she still has no idea, so while you take it out on her you still have us to deal with! You are a very sad and bitter lady. Ha, she even tried to appologize to you on her post but you being the pathetic retard breeder that you are wouldn't believe her....too bad for you! Poor baby now someone went and "borrowed" your money from PayPal I wonder how that happened???? Did you piss someone else off?? Haa Haaa! LOSER! Go ahead and report us-I will just sign on with another ID and keep you guessing! PS. Her name is Chris, but we call her ChrissyAnn because she is kind of a plain jane type and no OUR "act" didn't fall apart-we just can't use HER computer anymore...but guess what?? There are about 15 other computers to pick from so screw you and your retarded son. Oo dah oh err oooh <-- Your son wants you!"

Nice person huh? And Yahoo can't suspend all of her fake i.d.'s?

Oh, and since she keeps changing her name, here is her profile http://answers.yahoo.com/my/profile;_ylt=AqXp1XEtNBs7IiZ_HVT5s81y7hR.;_ylv=3?show=rExcZfF7aa

Answer 1

Site security monitors for repetitive program actions and automatically sets blocks against any it finds. This after the program has broken firewalls, encryption and passwords.

Answer 2

There are many billions of different combinations of numbers, for example, in a 5 digit number, there are
5 * 5 * 5 * 5 * 5 or 5 ^ 5 = 315
in a 10 digit number:
10 ^ 10 = 10,000,000,000

There is also the time factor. If each time you try, it opens a webpage which takes 5 seconds to load, that's gonna take a long, long time to try all the numbers

Also, sites like Paypal have methods of preventing this, such as blocking a user from logging on for a while after 3 or so unsuccessful logons

Answer 3

Brute forcing through checks? Nothing stops them, but keep in mind all attempts to use that information will be logged. If PayPal has 5 million tests for information from IP 123.123.123.123, guess what they're going to think? They're going to think that person is just trying to break into something. Most systems will cut someone off after they realize someone trying this 3 times and failing. People who know their information should need at most 2 tries to enter it correctly, and 99% of the time only one.