MINNEAPOLIS (WCCO) – The Secret Service said Wednesday that it’s investigating a data breach incident involving Target.

The investigation is being handled by the Electronic Crimes Task Force, which only works on major cases.

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According to the Wall Street Journal, thieves got the information off magnetic strips on shoppers’ cards.

The newspaper says it happened on Black Friday weekend, affecting 40,000 credit card devices at registers in stores across the country.

Information on the magnetic strips can be used to make counterfeit cards.

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Professor William McGeveran of the University of Minnesota, an expert on data privacy, says the way the thieves got that information is unusual.

“A lot of breaches you hear about you hear data was breached, and it turns out it’s just a lost laptop with a bunch of people’s information on it,” McGeveran said. “Based on the information we’re hearing here, it sounds like the actual payment software was hacked with a piece of malware or some other kind of security breach in the actual credit card processing itself. That’s not very common.”

Target hasn’t returned any requests for comment.

McGeveran said there’s nothing shoppers can do to prevent this type of thing.

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But if you are part of a breach in Minnesota, laws protect you so you have to be notified right away and then it would likely be up to the card company to help you out.

Susan-Elizabeth Littlefield