Yesterday, the U.S. Department of Justice announced that one of the leading email spammers has been arrested as part of an operation to disrupt and dismantle the infamous Kelihos botnet.

The Kelihos botnet is a network of tens of thousands of computers that are used to launch massive spamming campaigns comprising millions of emails. Those spam emails are used for a variety of nefarious purposes including the distribution of ransomware and malware. The botnet has been extensively used to spread fake antivirus software and spread credential-stealing malware.

Computers are added to the Kelihos botnet using malware. Once installed, Kelihos malware runs silently and users are unaware that their computers have been hijacked. The Kelihos botnet can be quickly weaponized and used for a variety of malicious purposes. The botnet has previously been used for spamming campaigns that artificially inflate stock prices, promote counterfeit drugs and recruit people to fraudulent work-at-home schemes.

Pyotr Levashov is believed to operate the botnet in addition to conducting a wide range of cybercriminal activities out of Russia. In what turned out to be an unwise move, Levashov left the relative safety of his home country and travelled to Barcelona, Spain on holiday. Levashov was arrested on Sunday, April 9 by Spanish authorities acting on a U.S. issued international arrest warrant.

Levashov is suspected of playing a role in the alleged Russian interference in the U.S. presidential election in 2016, although Levashov is best known for his spamming activities, click fraud and DDoS attacks.

Levashov, or Peter Severa as he is otherwise known, is heavily involved in distributing virus spamming software and is believed to have written numerous viruses and Trojans. Spamhaus lists Levashov in seventh place on the list of the 10 worst spammers.

Levashov is believed to have run multiple operations that connected virus developers with spamming networks, and is suspected of running the Kelihos botnet, the Waledac botnet – which was taken down in 2010 – and the Storm botnet.  Levashov was indicted for his role in the latter in 2009, although he managed to avoid extradition to the United States. At the time, Storm was the biggest spamming botnet in operation and was used to send millions of emails every day. Levashov also moderates many spamming forums and is well known in underground circles. Levashov is believed to have been extensively involved in spamming and other cybercriminal activities for the past 20 years; although to date he has avoided prosecution.

A statement released by the U.S. Department of Justice reads, “The operation announced today targeted an ongoing international scheme that was distributing hundreds of millions of fraudulent e-mails per year, intercepting the credentials to online and financial accounts belonging to thousands of Americans, and spreading ransomware throughout our networks.”

The DOJ operation also involved the takedown of domains associated with the Kelihos botnet starting on April 8, 2017. The DOJ says shutting down those domains was “an extraordinary task.”

While it is certainly good news that such a high profile and prolific spammer has been arrested and the Kelihos botnet has been severely disrupted, other spammers are likely to soon take Levashov’s place. Vitali Kremez, director of research at Flashpoint said his firm had seen chatter on underground forums indicating other major spammers are responding to the news of the arrest by taking acting to secure their own operations. There may be a blip in email spam volume, but that blip is only likely to be temporary.