Millions of Credit Card Numbers Nabbed in Payment System Breach by Tim Stevens, posted Jan 21st 2009 at 9:50AM It wasn't all that long ago that grocery shoppers at Hannaford were sent reeling with the news that their credit cards had been nabbed by hackers -- 4.2 million credit card numbers were stolen in total. If that was you, chances are you still haven't memorized your new credit card number, and that's just as well because you may need yet another one, as another breach has been identified -- one that may cover hundreds of millions of credit card users. St. Louis-based Heartland Payment announced yesterday that hackers gained access to the machines it uses to process roughly 100 million credit card transactions every month. The company handles transactions for 175,000 separate businesses and bills itself as having "the highest standards" and "the most trusted transactions." Despite that, the company has no idea how long its systems were being monitored, saying only that it was "longer than weeks." Because of this nobody knows just how many cards were compromised, but given the sheer volume of cards that are processed, many are already calling this the largest data breach in history. Until they're able to figure out just who was affected, Mastercard and Visa are now warning all cardholders and banks to watch out for suspicious activity, even if they may not have been affected. If there's some good news it's that only credit card numbers were nabbed, not addresses, so exposure should be somewhat limited. But regardless, the cost of sending millions of letters and millions of replacement cards will surely be massive, and given current economic conditions we're not sure just where all that money will come from. [From: USA Today]