A Ukrainian national who prosecutors say was part of a dark web network that illegally sold millions of personal Social Security numbers has pleaded guilty to cybercrime charges and is facing up to 15 years in federal prison.

Vitalii Chychasov made more than $19 million through a series of websites, known as the SSNDOB Marketplace that sold names, dates of birth and Social Security numbers belonging to people in the United States, according to a news release Tuesday from the U.S. Attorney’s Office. The SSNDOB scheme, which stands for social security number date of birth, impacted about 24 million people across the U.S., the Internal Revenue Service says. 

Chychasov pleaded guilty to conspiracy to commit access device fraud and trafficking in unauthorized access devices through the online scheme. He was arrested when he tried to enter Hungary in March 2022, federal prosecutors said, and extradited to the US four months later. 

Sergey Pugach, another suspected administrator in the scheme, was arrested that May, according to prosecutors. Last June, the websites were shut down through seizure orders issued against the domain names.

As part of his plea agreement, Chychasov agreed to a forfeiture money judgment for $5 million and to forfeit the internet domains, blackjob.biz, ssndob.club, ssndob.vip, and ssndob.ws, which were part of the SSNDOB operation.

Police in Cyprus and Latvia worked with the Federal Bureau of Investigation and Internal Revenue Service on dismantling the scheme, according to the release. 

The SSNDOB administrators posted ads on dark web criminal forums for the website’s services, the release said, and protected their anonymity and operation by “strategically maintaining servers in various countries, and requiring buyers to use digital payment methods.”