A hacker partly responsible for creating the highly sophisticated Gozi trojan that ripped tens of millions of dollars from victims has walked away with 21 months time served.

New York district judge Kimba Wood ruled Deniss Calovskis, 30, had paid sufficient penalty for what is described as his minor role in developing Gozi.

The trojan is the handiwork of Russian coder Nikita Kuzmin, 28, and was spread by Romanian hacker Mihai Ionut Paunescu, 31, both of whom are in custody in the US and Romania respectively having been arrested in January 2013.

The trojan was the infection mechanism for the group's moneymaking 76 Service, a turnkey offering sold on criminal forums.

Customers would infect victim machines with Gozi, and pay for 76 Service to have complex bank phishing pages spun up that would allow accounts to be drained while appearing unaltered to the victim.

Calovskis, known as Miami, helped write code for the phishing pages.

All told more than a million computers including those located at NASA are said to have been infected.

One unnamed investigator told KrebsonSecurity at the time of arrests 76 Service was akin to "Salesforce for bad guys".

"As a customer, you’d tell him which banks you wanted to target, and he has close-knit relationships with people who can code together pre-coded scripts to interact specifically with those bank Web sites, or has developers on standby to meet your needs," he told the publication.

The FBI chalked up the arrest of all three as a major win.

Judge Wood said of Calovskis' release "the goal of punishment has been served already".

Calovskis said he was tight on cash during the time of the offence, also an regional economic crisis, adding his father was developing cancer.

He has been ordered to forfeit US$1,000 and could return to Latvia within weeks. ®