Administrator of RSOCKS Proxy Botnet Pleads Guilty

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.”

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.”

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.

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.

Accused Russian RSOCKS Botmaster Arrested, Requests Extradition to U.S.

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.”

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.

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.

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.

No SOCKS, No Shoes, No Malware Proxy Services!

With the recent demise of several popular “proxy” services that let cybercriminals route their malicious traffic through hacked PCs, there is now something of a supply chain crisis gripping the underbelly of the Internet. Compounding the problem, several remaining malware-based proxy services have chosen to block new registrations to avoid swamping their networks with a sudden influx of customers.

Last week, a seven-year-old proxy service called 911[.]re abruptly announced it was permanently closing after a cybersecurity breach allowed unknown intruders to trash its servers and delete customer data and backups. 911 was already akin to critical infrastructure for many in the cybercriminal community after its top two competitors — VIP72 and LuxSocks — closed or were shut down by authorities over the past 10 months.

The underground cybercrime forums are now awash in pleas from people who are desperately seeking a new supplier of abundant, cheap, and reliably clean proxies to restart their businesses. The consensus seems to be that those days are now over, and while there are many smaller proxy services remaining, few of them on their own are capable of absorbing anywhere near the current demand.

“Everybody is looking for an alternative, bro,” wrote a BlackHatForums user on Aug. 1 in response to one of many “911 alternative” discussion threads. “No one knows an equivalent alternative to 911[.]re. Their service in terms of value and accessibility compared to other proxy providers was unmatched. Hopefully someone comes with a great alternative to 911[.]re.”

Among the more frequently recommended alternatives to 911 is SocksEscort[.]com, a malware-based proxy network that has been in existence since at least 2010. Here’s what part of their current homepage looks like:

But faced with a deluge of new signups in the wake of 911’s implosion, SocksEscort was among the remaining veteran proxy services that opted to close its doors to new registrants, replacing its registration page with the message:

“Due to unusual high demand, and heavy load on our servers, we had to block all new registrations. We won’t be able to support our proxies otherwise, and close SocksEscort as a result. We will resume registrations right after demand drops. Thank you for understanding, and sorry for the inconvenience.”

According to Spur.us, a startup that tracks proxy services, SocksEscort is a malware-based proxy offering, which means the machines doing the proxying of traffic for SocksEscort customers have been infected with malicious software that turns them into a traffic relay.

Spur says SocksEscort’s proxy service relies on software designed to run on Windows computers, and is currently leasing access to more than 14,000 hacked computers worldwide. That is a far cry from the proxy inventory advertised by 911, which stood at more than 200,000 IP addresses for rent just a few days ago.

SocksEscort is what’s known as a “SOCKS Proxy” service. The SOCKS (or SOCKS5) protocol allows Internet users to channel their Web traffic through a proxy server, which then passes the information on to the intended destination. From a website’s perspective, the traffic of the proxy network customer appears to originate from a rented/malware-infected PC tied to a residential ISP customer, not from the proxy service customer.

These services can be used in a legitimate manner for several business purposes — such as price comparisons or sales intelligence — but they are massively abused for hiding cybercrime activity because they make it difficult to trace malicious traffic to its original source.

The disruption at 911[.]re came days after KrebsOnSecurity published an in-depth look at the long-running proxy service, which showed that 911 had a history of incentivizing the installation of its proxy software without user notice or consent, and that it actually ran some of these “pay-per-install” schemes on its own to guarantee a steady supply of freshly-hacked PCs.

More on SocksEscort in an upcoming story.

Further reading:

July 29, 2022: 911 Proxy Service Implodes After Disclosing Breach

July 28, 2022: Breach Exposes Users of Microleaves Proxy Service

July 18, 2022: A Deep Dive Into the Residential Proxy Service ‘911’

June 28, 2022: The Link Between AWM Proxy & the Glupteba Botnet

June 22, 2022: Meet the Administrators of the RSOCKS Proxy Botnet

Sept. 1, 2021: 15-Year-Old Malware Proxy Network VIP72 Goes Dark

Breach Exposes Users of Microleaves Proxy Service

Microleaves, a ten-year-old proxy service that lets customers route their web traffic through millions of Microsoft Windows computers, recently fixed a vulnerability in their website that exposed their entire user database. Microleaves claims its proxy software is installed with user consent, but data exposed in the breach shows the service has a lengthy history of being supplied with new proxies by affiliates incentivized to distribute the software any which way they can — such as by secretly bundling it with other titles.

Launched in 2013, Microleaves is a service that allows customers to route their Internet traffic through PCs in virtually any country or city around the globe. Microleaves works by changing each customer’s Internet Protocol (IP) address every five to ten minutes.

The service, which accepts PayPal, Bitcoin and all major credit cards, is aimed primarily at enterprises engaged in repetitive, automated activity that often results in an IP address being temporarily blocked — such as data scraping, or mass-creating new accounts at some service online.

In response to a report about the data exposure from KrebsOnSecurity, Microleaves said it was grateful for being notified about a “very serious issue regarding our customer information.”

Abhishek Gupta is the PR and marketing manager for Microleaves, which he said in the process of being rebranded to “Shifter.io.” Gupta said the report qualified as a “medium” severity security issue in Shifter’s brand new bug bounty program (the site makes no mention of a bug bounty), which he said offers up to $2,000 for reporting data exposure issues like the one they just fixed. KrebsOnSecurity declined the offer and requested that Shifter donate the amount to the Electronic Frontier Foundation (EFF), a digital rights group.

From its inception nearly a decade ago, Microleaves has claimed to lease between 20-30 million IPs via its service at any time. Riley Kilmer, co-founder of the proxy-tracking service Spur.us, said that 20-30 million number might be accurate for Shifter if measured across a six-month time frame. Currently, Spur is tracking roughly a quarter-million proxies associated with Microleaves/Shifter each day, with a high rate of churn in IPs.

Early on, this rather large volume of IP addresses led many to speculate that Microleaves was just a botnet which was being resold as a commercial proxy service.

The very first discussion thread started by the new user Microleaves on the forum BlackHatWorld in 2013 sought forum members who could help test and grow the proxy network. At the time, the Microleaves user said their proxy network had 150,000 IPs globally, and was growing quickly.

One of BlackHatWorld’s moderators asked the administrator of the forum to review the Microleaves post.

“User states has 150k proxies,” the forum skeptic wrote. “No seller on BHW has 150k working daily proxies none of us do. Which hints at a possible BOTNET. That’s the only way you will get 150k.”

Microleaves has long been classified by antivirus companies as adware or as a “potentially unwanted program” (PUP), the euphemism that antivirus companies use to describe executable files that get installed with ambiguous consent at best, and are often part of a bundle of software tied to some “free” download. Security vendor Kaspersky flags the Microleaves family of software as a trojan horse program that commandeers the user’s Internet connection as a proxy without notifying the user.

“While working, these Trojans pose as Microsoft Windows Update,” Kaspersky wrote.

In a February 2014 post to BlackHatWorld, Microleaves announced that its sister service — reverseproxies[.]com — was now offering an “Auto CAPTCHA Solving Service,” which automates the solving of those squiggly and sometimes frustrating puzzles that many websites use to distinguish bots from real visitors. The CAPTCHA service was offered as an add-on to the Microleaves proxy service, and ranged in price from $20 for a 2-day trial to $320 for solving up to 80 captchas simultaneously.

“We break normal Recaptcha with 60-90% success rate, recaptcha with blobs 30% success, and 500+ other captcha,” Microleaves wrote. “As you know all success rate on recaptcha depends very much on good proxies that are fresh and not spammed!”

WHO IS ACIDUT?

The exposed Microleaves user database shows that the first user created on the service — username “admin” — used the email address alex.iulian@aol.com. A search on that email address in Constella Intelligence, a service that tracks breached data, reveals it was used to create an account at the link shortening service bit.ly under the name Alexandru Florea, and the username “Acidut.” [Full disclosure: Constella is currently an advertiser on this website].

According to the cyber intelligence company Intel 471, a user named Acidut with the email address iulyan87_4u@gmail.com had an active presence on almost a dozen shadowy money-making and cybercrime forums from 2010 to 2017, including BlackHatWorld, Carder[.]pro, Hackforums, OpenSC, and CPAElites.

In a 2011 post on Hackforums, Acidut said they were building a botnet using an “exploit kit,” a set of browser exploits made to be stitched into hacked websites and foist malware on visitors. Acidut claimed their exploit kit was generating 3,000 to 5,000 new bots each day. OpenSC was hacked at one point, and its private messages show Acidut purchased a license from Exmanoize, the handle used by the creator of the Eleonore Exploit Kit.

By November 2013, Acidut was advertising the sale of “26 million SOCKS residential proxies.” In a March 2016 post to CPAElites, Acidut said they had a worthwhile offer for people involved in pay-per-install or “PPI” schemes, which match criminal gangs who pay for malware installs with enterprising hackers looking to sell access to compromised PCs and websites.

Because pay-per-install affiliate schemes rarely impose restrictions on how the software can be installed, such programs can be appealing for cybercriminals who already control large collections of hacked machines and/or compromised websites. Indeed, Acidut went a step further, adding that their program could be quietly and invisibly nested inside of other programs.

“For those of you who are doing PPI I have a global offer that you can bundle to your installer,” Acidut wrote. “I am looking for many installs for an app that will generate website visits. The installer has a silence version which you can use inside your installer. I am looking to buy as many daily installs as possible worldwide, except China.”

Asked about the source of their proxies in 2014, the Microleaves user responded that it was “something related to a PPI network. I can’t say more and I won’t get into details.”

Acidut authored a similar message on the forum BlackHatWorld in 2013, where they encouraged users to contact them on Skype at the username “nevo.julian.” That same Skype contact address was listed prominently on the Microleaves homepage up until about a week ago when KrebsOnSecurity first reached out to the company.

ONLINE[.]IO (NOW MERCIFULLY OFFLINE)

There is a Facebook profile for an Alexandru Iulian Florea from Constanta, Romania, whose username on the social media network is Acidut. Prior to KrebsOnSecurity alerting Shifter of its data breach, the Acidut profile page associated Florea with the websites microleaves.com, shrooms.io, leftclick[.]io, and online[.]io. Mr. Florea did not respond to multiple requests for comment, and his Facebook page no longer mentions these domains.

Leftclick and online[.]io emerged as subsidiaries of Microleaves between 2017 and 2018. According to a help wanted ad posted in 2018 for a developer position at online[.]io, the company’s services were brazenly pitched to investors as “a cybersecurity and privacy tool kit, offering extensive protection using advanced adblocking, anti-tracking systems, malware protection, and revolutionary VPN access based on residential IPs.”

“Online[.]io is developing the first fully decentralized peer-to-peer networking technology and revolutionizing the browsing experience by making it faster, ad free, more reliable, secure and non-trackable, thus freeing the Internet from annoying ads, malware, and trackers,” reads the rest of that help wanted ad.

Microleaves CEO Alexandru Florea gave an “interview” to the website Irishtechnews.ie in 2018, in which he explained how Online[.]io (OIO) was going to upend the online advertising and security industries with its initial coin offering (ICO). The word interview is in air quotes because the following statements by Florea deserved some serious pushback by the interviewer.

“Online[.]io solution, developed using the Ethereum blockchain, aims at disrupting the digital advertising market valued at more than $1 trillion USD,” Alexandru enthused. “By staking OIO tokens and implementing our solution, the website operators will be able to access a new non-invasive revenue stream, which capitalizes on time spent by users online.”

“At the same time, internet users who stake OIO tokens will have the opportunity to monetize on the time spent online by themselves and their peers on the World Wide Web,” he continued. “The time spent by users online will lead to ICE tokens being mined, which in turn can be used in the dedicated merchant system or traded on exchanges and consequently changed to fiat.”

Translation: If you install our proxy bot/CAPTCHA-solver/ad software on your computer — or as an exploit kit on your website — we’ll make millions hijacking ads and you will be rewarded with heaps of soon-to-be-worthless shitcoin. Oh, and all your security woes will disappear, too.

It’s unclear how many Internet users and websites willingly agreed to get bombarded with Online[.]io’s annoying ads and search hijackers — and to have their PC turned into a proxy or CAPTCHA-solving zombie for others. But that is exactly what multiple security companies said happened when users encountered online[.]io, which operated using the Microsoft Windows process name of “online-guardian.exe.”

Incredibly, Crunchbase says Online[.]io raised $6 million in funding for an initial coin offering in 2018, based on the plainly ludicrous claims made above. Since then, however, online[.]io seems to have gone…offline, for good.

SUPER TECH VENTURES?

Until this week, Shifter.io’s website also exposed information about its customer base and most active users, as well as how much money each client has paid over the lifetime of their subscription. The data indicates Shifter has earned more than $11.7 million in direct payments, although it’s unclear how far back in time those payment records go, or how complete they are.

The bulk of Shifter customers who spent more than $100,000 at the proxy service appear to be digital advertising companies, including some located in the United States. None of the several Shifter customers approached by KrebsOnSecurity agreed to be interviewed.

Shifter’s Gupta said he’d been with the company for three years, since the new owner took over the company and made the rebrand to Shifter.

“The company has been on the market for a long time, but operated under a different brand called Microleaves, until new ownership and management took over the company started a reorganization process that is still on-going,” Gupta said. “We are fully transparent. Mostly [our customers] work in the data scraping niche, this is why we actually developed more products in this zone and made a big shift towards APIs and integrated solutions in the past year.”

Ah yes, the same APIs and integrated solutions that were found exposed to the Internet and leaking all of Shifter’s customer information.

Gupta said the original founder of Microleaves was a man from India, who later sold the business to Florea. According to Gupta, the Romanian entrepreneur had multiple issues in trying to run the company, and then sold it three years ago to the current owner — Super Tech Ventures, a private equity company based in Taiwan.

“Our CEO is Wang Wei, he has been with the company since 3 years ago,” Gupta said. “Mr. Florea left the company two years ago after ending this transition period.”

Google and other search engines seem to know nothing about a Super Tech Ventures based in Taiwan. Incredibly, Shifter’s own PR person claimed that he, too, was in the dark on this subject.

“I would love to help, but I really don’t know much about the mother company,” Gupta said, essentially walking back his “fully transparent” statement. “I know they are a branch of the bigger group of asian investment firms focused on private equity in multiple industries.”

Adware and proxy software are often bundled together with “free” software utilities online, or with popular software titles that have been pirated and quietly fused with installers tied to various PPI affiliate schemes.

But just as often, these intrusive programs will include some type of notice — even if installed as part of a software bundle — that many users simply do not read and click “Next” to get on with installing whatever software they’re seeking to use. In these cases, selecting the “basic” or “default” settings while installing usually hides any per-program installation prompts, and assumes you agree to all of the bundled programs being installed. It’s always best to opt for the “custom” installation mode, which can give you a better idea of what is actually being installed, and can let you control certain aspects of the installation.

Either way, it’s best to start with the assumption that if a software or service online is “free,” that there is likely some component involved that allows the provider of that service to monetize your activity. As KrebsOnSecurity noted at the conclusion of last week’s story on a China-based proxy service called 911, the rule of thumb for transacting online is that if you’re not the paying customer, then you and/or your devices are probably the product that’s being sold to others.

Further reading on proxy services:

July 18, 2022: A Deep Dive Into the Residential Proxy Service ‘911’
June 28, 2022: The Link Between AWM Proxy & the Glupteba Botnet
June 22, 2022: Meet the Administrators of the RSOCKS Proxy Botnet
Sept. 1, 2021: 15-Year-Old Malware Proxy Network VIP72 Goes Dark
Aug. 19, 2019: The Rise of “Bulletproof” Residential Networks