'Massive Data Breach' at Target May Involve 40 Million Customers

The Secret Service confirmed to USA TODAY that it is investigating the massive theft -- potentially involving 40 million shoppers' personal credit-card information.

The breach began on Black Friday, and continued until Dec. 15, according to the report. It's possible someone could have stolen information stored on the magnetic stripe on the backs of cards. If a pin number was acquired, the person can then use an ATM to withdraw cash from a customer's bank account. The thieves could also use the information to create counterfeit credit cards.

Target is based in Minneapolis, with almost 1,800 stores in the United States and 124 in Canada, according to its website. The data theft does not appear to involve online purchases.

Has anyone been affected by potential data theft at Target during this timespan?