When retailer TJX disclosed Jan. 17 that the computer systems that store data related to credit card, debit card, check, and merchandise return transactions had been broken into, it said it had discovered the hack in December. But security officials at Visa had been seeing an increase in fraudulent activity on credit and debit cards related to TJX properties, such as T.J. Maxx, Marshalls, and HomeGoods stores, since mid-November. That means it's possible the purloined consumer data has been floating around the Internet, available for purchase on black market Web sites and chat rooms, for at least two months, maybe longer.
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