(CBS) — There are concerns about a whole new data breach at a popular retailer: The Home Depot.

CBS 2’s Mike Parker reports on why there’s so much worry this time.

It appears that consumer data from Home Depot stores has been hacked from abroad and could lead to millions of identities being stolen. The hack job has been underway since April or May.

“We’re talking months of data being stolen by the bad guys who have now turned around and are selling the account numbers on the black market sites on the internet,” said Professor William Kresse at Governor’s State University

It has Home Depot shoppers unnerved. Shopper Dorian Wilkins says Tuesday was going to be the first time using her credit card at Home Depot and now he will think twice about it.

A company spokeswoman is saying, “Protecting our customers’ information is something we take extremely seriously and we are aggressively gathering facts at this point while working to protect customers.”

Fraud expert Kresse is concerned that the Russian hackers believed responsible, may have the Kremlin’s cooperation.

“This could be the first shot of a coming cyberwar,” Kresse said. “That would be extremely serious, that could do potentially devastating harm to the U.S. and western economies.”

The best advice for consumers: check your credit activity online, every day. Make sure every charge listed is one you actually made. If it isn’t call your credit card company.

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