Albert Gonzalez, 28, broke his own record for identity theft by hacking into retail networks, according to prosecutors, though they say his illicit computer exploits ended when he went to jail on charges stemming from a previous case.
Gonzalez is a former informant for the U.S. Secret Service who helped the agency hunt hackers, authorities say. The agency later found out that he had also been working with criminals and feeding them information on ongoing investigations, even warning off at least one individual, according to authorities.
Gonzalez, was indicted Monday in New Jersey and charged with conspiring with two other unnamed suspects to steal the private information.
Prosecutors say Gonzalez, who is known online as "soupnazi," targeted customers of convenience store giant 7-Eleven Inc. and supermarket chain Hannaford Brothers, Co. Inc. They also targeted Heartland Payment Systems, a New Jersey-based card payment processor.
He faces up to 20 years in prison if convicted of the new charges.
Gonzalez is already due to go on trial in New York next month for allegedly helping hack the computer network of the national restaurant chain Dave and Buster's.
The Justice Department said the new case represents the largest alleged credit and debit card data breach ever charged in the United States, beginning in October 2006.
Gonzalez allegedly devised a sophisticated attack to penetrate the computer networks, steal the card data, and send that data to computer servers in California, Illinois, Latvia, the Netherlands and Ukraine.
Also last year, the Justice Department announced additional charges against Gonzalez and others for hacking retail companies' computers for the theft of approximately 40 million credit cards. At the time, that was believed to be the biggest single case of hacking private computer networks to steal credit card data, puncturing the electronic defenses of retailers including Barnes & Noble, Sports Authority and OfficeMax.
At the time of those charges, officials said the alleged thieves weren't computer geniuses, just opportunists who used a technique called "wardriving," which involved cruising through different areas with a laptop computer and looking for accessible wireless Internet signals. Once they located a vulnerable network, they installed so-called "sniffer programs" that captured credit and debit card numbers as they moved through a retailer's processing networks.
Gonzalez faces a possible life sentence if convicted in that case.
Restaurants are among the most common targets for hackers, experts said, because they often fail to update their antivirus software and other computer security systems.