It may not have been the greatest hack ever, but police say the malicious software sneaked onto restaurant chain Dave & Buster's corporate network was good enough to earn criminals hundreds of thousands of dollars.

Three men have been charged with hacking into the network and then remotely installing "packet sniffer" software on point-of-sale servers at 11 Dave & Buster's locations throughout the U.S.

A packet sniffer logs information being sent over a network. In this case, the criminals used it to log credit- and payment-card data as it was sent from the branch locations to corporate headquarters.

The hacking took place from April to September 2007 and was lucrative, according to court filings. At Dave & Buster's Islandia, New York, location, for example, the hackers accessed details of about 5,000 payment cards. The information was sold to other criminals who then used the card numbers to scam online merchants. The criminals were able to post at least US$600,000 in fraudulent transactions from 675 cards taken from this one store.

Contacted by IDG News Service, the Islandia Dave & Buster's restaurant manager said he was unaware of any fraud being linked to his location. Dave & Buster's corporate offices did not return a call seeking comment.

Dave & Buster's operates about 50 restaurants in the U.S. The locations feature video games, billiards and arcade-style games.

The people charged are Maksym Yastremskiy, Aleksandr Suvorov and Albert Gonzalez. 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]," said Special Agent Matthew Lynch in a sworn statement filed in the case.

Gonzalez, who was arrested in Miami within the past two weeks, wrote the packet sniffing software, Lynch said. He was charged with one count of wire fraud conspiracy.

The three men charged in this case were arrested over the past year, but the case was sealed until Monday.

Unfortunately for the criminals, Gonzalez's code had some problems, according to Lynch.

In April 2007 it bombed its first test, on a point-of-sale server at the Dave & Buster's in Arundel, Maryland. "The packet sniffer malfunctioned ... and no credit or debit card account information was captured, " Lynch said.

Even when the packet sniffer worked, the hackers were forced to keep returning to the Dave & Buster's network and restarting their malicious software, Lynch said. A bug in the packet sniffer caused it to shut down whenever the computer it was monitoring rebooted.

International cyber criminals often see poorly secured retail computer networks as an easy source for credit card information.

Cyber thieves used similar techniques in the massive 2006 TJ Maxx data breach, stealing credit card numbers from the company's computer system and then using them for purchases at stores like Wal-Mart. Court filings suggest that more than 94 million accounts may have been affected in that case.