On Thursday, retailer Target announced that between November 27 and December 15 its point-of-sale systems – the cash registers mounted at the check-out areas of its stores – suffered an attack that exposed an estimated 40 million credit and debit card numbers. The company announced that it has “alerted authorities and financial institutions immediately after it was made aware of the unauthorized access, and is putting all appropriate resources behind these efforts.” It said it has hired outside support to investigate the source and method of the breach. Thieves made off with customer names, card numbers, as well as expiration dates and the three-digit CVV security code. Only customers who visited Target stores were compromised.