A massive security breach at Target Corp. may affect millions of customer credit and debit cards used over the busy Black Friday weekend in stores nationwide, multiple sources reported Wednesday.
The Wall Street Journal reported the Minneapolis-based retailer was struck by an extensive theft that is currently being investigated by the Secret Service; however, details were few.
Forbes reported that the compromised data involves the type stored on the magnetic strip of cards that were used at stores, and the breach apparently stretches to all Target store locations nationwide. The website, however, is not believed to have been affected.
The breach came to light in a Krebs on Security article that cites two of the top 10 credit card issues as sources, including one anti-fraud analyst who said the breach window is expanding and customers across the U.S. were victimized.
According to computer security expert Brian Krebs, the breach was initially thought to have extended from just after Thanksgiving through Dec. 6, but investigators recently discovered the breach may have extended as far as Dec. 15.
An unknown number of customers have been affected, but the unnamed sources in the Krebs on Security article both said at least a million cards were compromised, and that it could be one of the largest retail breaches in history.
The Star Tribune cited a spokeswoman from American Express Co., who confirmed that the company is aware of the breach and has put fraud controls in place; however, the company has not noticed any fraudulent activities on its customers' cards.
Krebs also told the Star Tribune by phone that the breach came to light because credit card companies notified banks, but he did not know how the breach occurred or whether the data has been used to commit fraud.
The data stolen would allow crooks to counterfeit cards by encoding the information onto any card that has a magnetic stripe, according to Krebs. If the thieves were able to intercept PIN data in debit transactions, they may be able to recreate debit cards and withdraw cash at ATMs, Krebs on Security warned.
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