Last month, agents from the DHS's Immigration and Customs Enforcement (ICE) investigations unit raided the home of two Vietnamese exchange students at Minnesota's Winona State University, seizing documents and computer equipment.

According to an the students, Tram Vo and Khoi Van, made more than $1.2 million selling software, videogames and Apple gift cards on eBay, and then shipping buyers products that they'd purchased with stolen credit card numbers.

The scam that Vo and Van are accused of has become a big problem for U.S. merchants, according to the affidavit, which was unsealed last week.

Here's how it works. Using stolen information the criminals set up eBay and PayPal accounts in other people's names and start selling products -- $400 Rosetta Stone software or iTunes gift cards, for example. When legitimate buyers purchase these products using PayPal, the scammers then order them direct from the manufacturer, using stolen credit card numbers. By the time the credit card user reports the fraud, the scammers have already moved their money from PayPal to another bank account. Then they move it offshore to accounts in Canada or Vietnam.

The online merchant is the big loser in the deal, but the consumers whose information was stolen also take a hit, as they have to untangle themselves from the fraudulent credit card transactions and fake eBay and PayPal accounts.