When it comes to breaches, everybody's talking about the latest hacks and the biggest data losses. But it was an old hack -- and a relatively small target -- that netted more than half a million dollars for a group of cybercriminals last year.

The hack, which was revealed Monday after the U.S. Secret Service arrested three individuals suspected of originating it, was initiated by installing packet sniffer software on point-of-sale machines at 11 locations of Dave & Buster's, a 50-site restaurant chain that also offers a video arcade and other games.

The attackers were able to steal information on some 5,000 credit card accounts by monitoring transactions from cash registers at Dave & Buster's Islandia, N.Y., location alone, according to court documents. The thieves tapped 675 of those credit cards to steal more than $600,000.

Using an approach similar to the one used in the infamous TJX attack last year, the criminals stole data in transit from branch-office retail locations to corporate headquarters, the documents said. In a statement, however, Dave & Buster's officials said they do not store any credit card data, as TJX did.

Sniffers have been used for more than a decade to tap into data network traffic and peek at the contents. In the case of Dave & Buster's, the sniffers were used to access data transmitted over wired connections, rather than wireless transmissions, as is alleged in the TJX case. Officials at Dave & Buster's say the chain has taken steps to close the vulnerability so that it can't happen in the future.

Maksym Yastremskiy, Aleksandr Suvorov, and Albert Gonzalez have been arrested in the case. Yastremskiy and Suvorov are being held in Turkey and Germany, respectively, and face fraud and computer hacking charges.

Yastremskiy "was one of the biggest resellers of stolen credit card data targeted by the USSS [United States Secret Service]," according to officials at the agency.

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