The man federal prosecutors say operated the Kelihos botnet has now pleaded guilty

During a hearing in federal court in Hartford, Connecticut, on Wednesday, Peter Yuryevich Levashov admitted guilt in one count of causing intentional damage to a protected computer, one count of conspiracy, one count of wire fraud, and one count of aggravated identity theft.

The 38-year-old Russian’s botnet, which dated back to 2010, spanned more than 10,000 machines and was primarily used to send out spam, steal logins, distribute ransomware, and more. Federal authorities shut it down in 2017.

"For over two decades, Peter Levashov operated botnets which enabled him to harvest personal information from infected computers, disseminate spam, and distribute malware used to facilitate multiple scams," said Assistant Attorney General Brian Benczkowski in a statement.

The Department of Justice said that Levashov "controlled and operated multiple botnets, including the Storm, Waledac, and Kelihos botnets to harvest personal information and means of identification (including email addresses, usernames and logins, and passwords) from infected computers."

In 2009, he was formally charged in the District of Columbia with operating the "Storm" botnet. As Ars has previously reported, Levashov has long been on a list of the World's Ten Worst Spammers, maintained by antispam volunteer organization Spamhaus.

Levashov was arrested in Barcelona, Spain, in April 2017 and was extradited to the United States in February 2018, where he has remained in custody. His sentencing has been scheduled for September 6, 2019.