UPDATE 3-Target probe eyes overseas hackers; stolen cards for sale online
December 20, 2013 at 20:35 PM EST
WASHINGTON, Dec 20 (Reuters) - Investigators believe that overseas hackers were responsible for the cyber attack on U.S. retailer Target Corp that compromised up to 40 million payment cards during the first three weeks of the holiday shopping season, a person familiar with the matter said on Friday.