Nightly News | December 19, 2013
>>> good evening. it's the closest thing to a national credit card hacking this nation has ever seen. 40 million americans who shopped at target stores between thanksgiving and december 15 may have had their information stolen and now may need new security pins, passwords or cards. it appears the hackers found a way to access the checkout system. every checkout inside every target store in the u.s. and canada when the card was swiped the information was, too. it's an unprecedented security breach for a store chain of this size. it sent a chill through the retailing business and is causing massive problems for target customers across the country. we begin with tom costello.
>> reporter: yet another massive data heist, this time the target was target. a banner notice on the company website warns customers of unauthorized access to payment card data in u.s. stores. a staggering 40 million credit and debit cards compromised at 1,800 stores nationwide from november 27 to december 15. in chicago, chrissy yurko noticed her balance suddenly dropped.
>> noticed, whoa, my bank account is pretty low. i was scrolling through and saw $ 1273 charge to the microsoft store.
>> reporter: then came the bank's overdraft alert. it is happening to customers across the country. thieves appear to have gotten away with everything on the magnetic strip -- name, account number , expiration date and the three-digit security code. making matters worse, the cyber thieves struck just as black friday and the christmas rush kicked in.
>> chief suspect would be sophisticated organized criminals that studied target or insiders with privileged access that know exactly where to go.
>> reporter: in a statement target said it is working closely with law enforcement and financial institutions and moved swiftly to address the issue so guests can shop with confidence. some consumer advocates say if you used your credit or debit card you may want to take action.
>> cancel your card. get a new number. that's the shortest, easiest answer to protect yourself from the risk of fraudulent charges.
>> reporter: security experts recommend closely monitoring your bank and credit card statements for unauthorized charges. to be cautious, use the debit card as a credit card and avoid entering your pin at stores. check your credit report regularly for signs someone has stolen your data or identity. how long should customers remain vigilant?
>> all citizens should continually check their credit history as well as your monthly billing statement.
>> reporter: a massive fraud. for millionses of americans, a massive headache. tom costello, nbc news, washington.