Even with the checksum digits, the keyspace for all possible credit card numbers is huge and largely unused. Also, if you get declined, you don't know whether it's a problem with the card number or the expiration date. There's no way to brute force issued card numbers independent of expiration dates, which would speed up the process greatly. So let's say that you're assuming that the expiration date is within three years. If you've got an unissued card number, you have to make all 36 attempts with it.
Also, CNN has revised their story. The new number is 5.6 million credit card numbers. Kevin. ----- Original Message ----- From: "Jason Coombs" <[EMAIL PROTECTED]> To: "Richard M. Smith" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Tuesday, February 18, 2003 1:00 PM Subject: RE: [Full-Disclosure] Hackers View Visa/MasterCard Accounts > AVS gives the merchant a clue as to whether or not there is high risk posed > by a particular alleged-customer. > > Merchants are free to ignore AVS, and many don't even bother to use it. > > Anyway, it doesn't impact the "declined" or "authorized" result given to a > shopper at an e-commerce site that implements real-time processing. > > Jason Coombs > [EMAIL PROTECTED] > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Richard M. > Smith > Sent: Tuesday, February 18, 2003 5:30 AM > To: [EMAIL PROTECTED] > Subject: RE: [Full-Disclosure] Hackers View Visa/MasterCard Accounts > > > Wouldn't the AVS system used by the credit card companies catch this > kind of hack? The AVS system does a rudimentary check to make sure that > the billing address given on a order is correct one for the credit card. > > Richard > > > _______________________________________________ > Full-Disclosure - We believe in it. > Charter: http://lists.netsys.com/full-disclosure-charter.html > _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
