Login
Denis Emelyantsev, a 36-year-old Russian man accused of running a massive botnet called RSOCKS that stitched malware into millions of devices worldwide, pleaded guilty to two counts of computer crime violations in a California courtroom this week. The plea comes just months after Emelyantsev was extradited from Bulgaria, where he told investigators, “America is looking for me because I have enormous information and they need it.”
A copy of the passport for Denis Emelyantsev, a.k.a. Denis Kloster, as posted to his Vkontakte page in 2019.
First advertised in the cybercrime underground in 2014, RSOCKS was the web-based storefront for hacked computers that were sold as “proxies” to cybercriminals looking for ways to route their Web traffic through someone else’s device.
Customers could pay to rent access to a pool of proxies for a specified period, with costs ranging from $30 per day for access to 2,000 proxies, to $200 daily for up to 90,000 proxies.
Many of the infected systems were Internet of Things (IoT) devices, including industrial control systems, time clocks, routers, audio/video streaming devices, and smart garage door openers. Later in its existence, the RSOCKS botnet expanded into compromising Android devices and conventional computers.
In June 2022, authorities in the United States, Germany, the Netherlands and the United Kingdom announced a joint operation to dismantle the RSOCKS botnet. But that action did not name any defendants.
Inspired by that takedown, KrebsOnSecurity followed clues from the RSOCKS botnet master’s identity on the cybercrime forums to Emelyantsev’s personal blog, where he went by the name Denis Kloster. The blog featured musings on the challenges of running a company that sells “security and anonymity services to customers around the world,” and even included a group photo of RSOCKS employees.
“Thanks to you, we are now developing in the field of information security and anonymity!,” Kloster’s blog enthused. “We make products that are used by thousands of people around the world, and this is very cool! And this is just the beginning!!! We don’t just work together and we’re not just friends, we’re Family.”
But by the time that investigation was published, Emelyantsev had already been captured by Bulgarian authorities responding to an American arrest warrant. At his extradition hearing, Emelyantsev claimed he would prove his innocence in an U.S. courtroom.
“I have hired a lawyer there and I want you to send me as quickly as possible to clear these baseless charges,” Emelyantsev told the Bulgarian court. “I am not a criminal and I will prove it in an American court.”
RSOCKS, circa 2016. At that time, RSOCKS was advertising more than 80,000 proxies. Image: archive.org.
Emelyantsev was far more than just an administrator of a large botnet. Behind the facade of his Internet advertising company based in Omsk, Russia, the RSOCKS botmaster was a major player in the Russian email spam industry for more than a decade.
Some of the top Russian cybercrime forums have been hacked over the years, and leaked private messages from those forums show the RSOCKS administrator claimed ownership of the RUSdot spam forum. RUSdot is the successor forum to Spamdot, a far more secretive and restricted community where most of the world’s top spammers, virus writers and cybercriminals collaborated for years before the forum imploded in 2010.
A Google-translated version of the Rusdot spam forum.
Indeed, the very first mentions of RSOCKS on any Russian-language cybercrime forums refer to the service by its full name as the “RUSdot Socks Server.”
Email spam — and in particular malicious email sent via compromised computers — is still one of the biggest sources of malware infections that lead to data breaches and ransomware attacks. So it stands to reason that as administrator of Russia’s most well-known forum for spammers, Emelyantsev probably knows quite a bit about other top players in the botnet spam and malware community.
It remains unclear whether Emelyantsev made good on his promise to spill that knowledge to American investigators as part of his plea deal. The case is being prosecuted by the U.S. Attorney’s Office for the Southern District of California, which has not responded to a request for comment.
Emelyantsev pleaded guilty on Monday to two counts, including damage to protected computers and conspiracy to damage protected computers. He faces a maximum of 20 years in prison, and is currently scheduled to be sentenced on April 27, 2023.
A 36-year-old Russian man recently identified by KrebsOnSecurity as the likely proprietor of the massive RSOCKS botnet has been arrested in Bulgaria at the request of U.S. authorities. At a court hearing in Bulgaria this month, the accused hacker requested and was granted extradition to the United States, reportedly telling the judge, “America is looking for me because I have enormous information and they need it.”
A copy of the passport for Denis Kloster, as posted to his Vkontakte page in 2019.
On June 22, KrebsOnSecurity published Meet the Administrators of the RSOCKS Proxy Botnet, which identified Denis Kloster, a.k.a. Denis Emelyantsev, as the apparent owner of RSOCKS, a collection of millions of hacked devices that were sold as “proxies” to cybercriminals looking for ways to route their malicious traffic through someone else’s computer.
A native of Omsk, Russia, Kloster came into focus after KrebsOnSecurity followed clues from the RSOCKS botnet master’s identity on the cybercrime forums to Kloster’s personal blog, which featured musings on the challenges of running a company that sells “security and anonymity services to customers around the world.” Kloster’s blog even included a group photo of RSOCKS employees.
“Thanks to you, we are now developing in the field of information security and anonymity!,” Kloster’s blog enthused. “We make products that are used by thousands of people around the world, and this is very cool! And this is just the beginning!!! We don’t just work together and we’re not just friends, we’re Family.”
The Bulgarian news outlet 24Chasa.bg reports that Kloster was arrested in June at a co-working space in the southwestern ski resort town of Bansko, and that the accused asked to be handed over to the American authorities.
“I have hired a lawyer there and I want you to send me as quickly as possible to clear these baseless charges,” Kloster reportedly told the Bulgarian court this week. “I am not a criminal and I will prove it in an American court.”
Launched in 2013, RSOCKS was shut down in June 2022 as part of an international investigation into the cybercrime service. According to the Justice Department, the RSOCKS botnet initially targeted Internet of Things (IoT) devices, including industrial control systems, time clocks, routers, audio/video streaming devices, and smart garage door openers; later in its existence, the RSOCKS botnet expanded into compromising additional types of devices, including Android devices and conventional computers, the DOJ said.
The Justice Department’s June 2022 statement about that takedown cited a search warrant from the U.S. Attorney’s Office for the Southern District of California, which also was named by Bulgarian news outlets this month as the source of Kloster’s arrest warrant.
When asked about the existence of an arrest warrant or criminal charges against Kloster, a spokesperson for the Southern District said, “no comment.”
Update, Sept. 24, 9:00 a.m. ET: Kloster was named in a 2019 indictment (PDF) unsealed Sept. 23 by the Southern District court.
The employees who kept things running for RSOCKS, circa 2016. Notice that nobody seems to be wearing shoes.
24Chasa said the defendant’s surname is Emelyantsev and that he only recently adopted the last name Kloster, which is his mother’s maiden name.
As KrebsOnSecurity reported in June, Kloster also appears to be a major player in the Russian email spam industry. In several private exchanges on cybercrime forums, the RSOCKS administrator claimed ownership of the RUSdot spam forum. RUSdot is the successor forum to Spamdot, a far more secretive and restricted forum where most of the world’s top spammers, virus writers and cybercriminals collaborated for years before the community’s implosion in 2010.
Email spam — and in particular malicious email sent via compromised computers — is still one of the biggest sources of malware infections that lead to data breaches and ransomware attacks. So it stands to reason that as administrator of Russia’s most well-known forum for spammers, the defendant in this case probably knows quite a bit about other top players in the botnet spam and malware community.
A Google-translated version of the Rusdot spam forum.
Despite maintaining his innocence, Kloster reportedly told the Bulgarian judge that he could be useful to American investigators.
“America is looking for me because I have enormous information and they need it,” Kloster told the court, according to 24Chasa. “That’s why they want me.”
The Bulgarian court agreed, and granted his extradition. Kloster’s fiancee also attended the extradition hearing, and reportedly wept in the hall outside the entire time.
Kloster turned 36 while awaiting his extradition hearing, and may soon be facing charges that carry punishments of up to 20 years in prison.
FreshRSS 