Four Russians and a Ukrainian are charged with heading up the biggest hacking and data breach scheme in U.S. history.

David Matthau, Townsquare Media NJ

Authorities say they targeted some of the world's biggest companies, stealing millions of debit and credit card numbers over a six year period, causing millions of dollars in losses.

"The scheme brought together some of the most experienced and skilled hackers in the world. They possessed the skills and the unique hacking tools to gain initial access to the victim companies," says U.S. Attorney for New Jersey Paul Fishman.

He says the ring scouted potential victim companies by researching their websites and other publications to identify how many financial transactions they were involved with.

"After identifying the websites of vulnerable companies that were engaging in these transactions, the defendants would attack the victims networks - what they would do is they would probe and test and penetrate until they would actually get in."

Fishman points out the hackers were "very patient and relentless- sometimes these attacks and these explorations would take months, and months and months. They would put programs on those networks called sniffers which would intercept credit and debit card information as it passed through those networks."

He also says the hackers and their associates orchestrated 17 major data breaches, including intrusions into the networks of NASDAQ, Seven Eleven, JC Penny, just to name a few.

The investigation was launched after a December of 2007 intrusion of a company here in New Jersey.