Anxious consumers besieged Target Corp. on Thursday after the company acknowledged that hackers may have gained access to credit and debit card information from 40 million shoppers.
The swarm of people who tried to access their Target Redcard account information online or who called customer service overwhelmed the company's systems, piling frustration on top of the questions surrounding the brazen attack.
Target confirmed early in the day that a data breach had potentially exposed card information from shoppers who made purchases in the company's nearly 1,800 U.S. stores between Nov. 27 and Dec. 15. Online transactions weren't affected, the company said.
The Minneapolis-based company said it took immediate steps to eliminate the problem once it was identified. The company didn't provide any explanation for how it happened, but a person familiar with the investigation said that malicious software was placed on Target's point-of-sale terminals near store registers, where customers swipe their cards.
Target spokeswoman Katie Boylan said the company's investigation is continuing. "This is obviously a sophisticated crime that we're dealing with," Boylan said.
A range of credit cards, including Visa, American Express and Target's own Redcard, were likely exposed, although the extent of the impact is far from clear.
Thieves accessed customers' names, credit and debit card numbers, card expiration dates and CVVs, the card verification value that shoppers know as the three-digit security number typically displayed on the back of their cards.
Boylan declined to answer questions about whether Target knows of customers who have seen fraudulent charges made on their cards as a result of the breach, which was disclosed by computer security blogger Brian Krebs on Wednesday.