Why Malware Crypting Services Deserve More Scrutiny

If you operate a cybercrime business that relies on disseminating malicious software, you probably also spend a good deal of time trying to disguise or “crypt” your malware so that it appears benign to antivirus and security products. In fact, the process of “crypting” malware is sufficiently complex and time-consuming that most serious cybercrooks will outsource this critical function to a handful of trusted third parties. This story explores the history and identity behind Cryptor[.]biz, a long-running crypting service that is trusted by some of the biggest names in cybercrime.

Virtually all malware that is deployed for use in data stealing at some point needs to be crypted. This highly technical, laborious process involves iteratively altering the appearance and behavior of a malicious file until it no longer sets off alarm bells when scanned by different antivirus tools.

Experienced malware purveyors understand that if they’re not continuously crypting their malware before sending it out, then a lot more of whatever digital disease they are trying to spread is going to get flagged by security tools. In short, if you are running a cybercrime enterprise and you’re not equipped to handle this crypting process yourself, you probably need to pay someone else to do it for you.

Thanks to the high demand for reliable crypting services, there are countless cybercriminals who’ve hung out their shingles as crypting service providers. However, most of these people do not appear to be very good at what they do, because most are soon out of business.

One standout is Cryptor[.]biz. This service is actually recommended by the purveyors of the RedLine information stealer malware, which is a popular and powerful malware kit that specializes in stealing victim data and is often used to lay the groundwork for ransomware attacks. Cryptor[.]biz also has been recommended to customers of the Vidar information stealer malware family (via the malware’s Telegram support channels).

WHO RUNS CRYPTOR[.]BIZ?

As good as Cryptor[.]biz may be at obfuscating malware, its proprietor does not appear to have done a great job covering his own tracks. The registration records for the website Cryptor[.]biz are hidden behind privacy protection services, but the site’s homepage says potential customers should register by visiting the domain crypt[.]guru, or by sending a Jabber instant message to the address “masscrypt@exploit.im.”

Crypt[.]guru’s registration records also are hidden, yet passive domain name system (DNS) records for both cryptor[.]biz and crypt[.]guru show that in 2018 the domains were forwarding incoming email to the address obelisk57@gmail.com.

Cyber intelligence firm Intel 471 reports that obelisk57@gmail.com was used to register an account on the forum Blacksoftware under the nickname “Kerens.” Meanwhile, the Jabber address masscrypt@exploit.im has been associated with the user Kerens on the Russian hacking forum Exploit from 2011 to the present day.

The very first post by Kerens on Exploit in 2011 was a negative review of a popular crypting service that predated Cryptor[.]biz called VIP Crypt, which Kerens accused of being “shitty” and unreliable. But Intel 471 finds that after his critical review of VIP Crypt, Kerens did not post publicly on Exploit again for another four years until October 2016, when they suddenly began advertising Cryptor[.]biz.

Intel 471 found that Kerens used the email address pepyak@gmail.com, which also was used to register Kerens accounts on the Russian language hacking forums Verified and Damagelab.

Ironically, Verified has itself been hacked multiple times over the years, with its private messages and user registration details leaked online. Those records indicate the user Kerens registered on Verified in March 2009 from an Internet address in Novosibirsk, a city in the southern Siberian region of Russia.

In 2010, someone with the username Pepyak on the Russian language affiliate forum GoFuckBiz[.]com shared that they typically split their time during the year between living in Siberia (during the milder months) and Thailand (when Novosibirsk is typically -15 °C/°5F).

For example, in one conversation about the best car to buy for navigating shoddy roads, Pepyak declared, “We have shitty roads in Siberia.” In January 2010, Pepyak asked the GoFuckBiz community where one might find a good USB-based modem in Phuket, Thailand.

DomainTools.com says the email address pepyak@gmail.com was used to register 28 domain names over the years, including a now-defunct Russian automobile sales website called “autodoska[.]biz.” DomainTools shows this website was registered in 2008 to a Yuri Churnov from Sevastpol, Crimea (prior to Russia’s annexation of Crimea in 2014, the peninsula was part of Ukraine).

The WHOIS records for autodoska[.]biz were changed in 2010 to Sergey Purtov (pepyak@gmail.com) from Yurga, a town in Russia’s Kemerovo Oblast, which is a relatively populous area in Western Siberia that is adjacent to Novosibirsk.

Many of the 28 domains registered to pepyak@gmail.com have another email address in their registration records: unforgiven57@mail.ru. According to DomainTools, the Unforgiven email address was used to register roughly a dozen domains, including three that were originally registered to Keren’s email address — pepyak@gmail.com (e.g., antivirusxp09[.]com).

One of the domains registered in 2006 to the address unforgiven57@mail.ru was thelib[.]ru, which for many years was a place to download pirated e-books. DomainTools says thelib[.]ru was originally registered to a Sergey U Purtov.

Most of the two-dozen domains registered to pepyak@gmail.com shared a server at one point with a small number of other domains, including mobile-soft[.]su, which was registered to the email address spurtov@gmail.com.

CDEK, an express delivery company based in Novosibirsk, was apparently hacked at some point because cyber intelligence firm Constella Intelligence found that its database shows the email address spurtov@gmail.com was assigned to a Sergey Yurievich Purtov (Сергей Юрьевич Пуртов).

DomainTools says the same phone number in the registration records for autodoska[.]biz (+7.9235059268) was used to secure two other domains — bile[.]ru and thelibrary[.]ru, both of which were registered to a Sergey Y Purtov.

A search on the phone number 79235059268 in Skype reveals these digits belong to a “Sergey” from Novosibirsk with the now-familiar username  — Pepyak.

Bringing things full circle, Constella Intelligence shows that various online accounts tied to the email address unforgiven57@mail.ru frequently relied on the somewhat unique password, “plk139t51z.” Constella says that same password was used for just a handful of other email addresses, including gumboldt@gmail.com.

Hacked customer records from CDEK show gumboldt@gmail.com was tied to a customer named Sergey Yurievich Purtov. DomainTools found that virtually all of the 15 domain names registered to gumboldt@gmail.com (including the aforementioned mobile-soft[.]su) were at one point registered to spurtov@gmail.com.

Intel 471 reports that gumboldt@gmail.com was used in 2009 to register a user by the nickname “Kolumb” on the Russian hacking forum Antichat. From Kolumb’s posts on Antichat, it seems this user was mostly interested in buying access to compromised computers inside of Russia.

Then in December 2009, Kolumb said they were in desperate need of a reliable crypting service or full-time cryptor.

“We need a person who will crypt software every day, sometimes even a couple of times a day,” Kolumb wrote on Antichat.

Mr. Purtov did not respond to requests for comment sent to any of the email addresses referenced in this report. Mail.ru responded that the email address spurtov@mail.ru is no longer active.

ANALYSIS

As KrebsOnSecurity opined on Mastodon earlier this week, it makes a lot of sense for cybersecurity researchers and law enforcement alike to focus attention on the top players in the crypting space — for several reasons. Most critically, the cybercriminals offering time-tested crypting services also tend to be among the most experienced and connected malicious coders on the planet.

Think of it this way: By definition, a crypting service scans and examines all types of malware before those new nasties are first set loose in the wild. This fact alone should make these criminal enterprises a primary target of cybersecurity firms looking to gain more timely intelligence about new malware.

Also, a review of countless posts and private messages from Pepyak and other crypting providers shows that a successful crypting service will have direct and frequent contact with some of the world’s most advanced malware authors.

In short, infiltrating or disrupting a trusted crypting service can be an excellent way to slow down or even sideline a large number of cybercrime operations all at once.

Further reading on the crypting industry:

This Service Helps Malware Authors Fix Flaws in Their Code
Antivirus is Dead: Long Live Antivirus!

Interview With a Crypto Scam Investment Spammer

Social networks are constantly battling inauthentic bot accounts that send direct messages to users promoting scam cryptocurrency investment platforms. What follows is an interview with a Russian hacker responsible for a series of aggressive crypto spam campaigns that recently prompted several large Mastodon communities to temporarily halt new registrations. According to the hacker, their spam software has been in private use until the last few weeks, when it was released as open source code.

Renaud Chaput is a freelance programmer working on modernizing and scaling the Mastodon project infrastructure — including joinmastodon.org, mastodon.online, and mastodon.social. Chaput said that on May 4, 2023, someone unleashed a spam torrent targeting users on these Mastodon communities via “private mentions,” a kind of direct messaging on the platform.

The messages said recipients had earned an investment credit at a cryptocurrency trading platform called moonxtrade[.]com. Chaput said the spammers used more than 1,500 Internet addresses across 400 providers to register new accounts, which then followed popular accounts on Mastodon and sent private mentions to the followers of those accounts.

Since then, the same spammers have used this method to advertise more than 100 different crypto investment-themed domains. Chaput said that at one point this month the volume of bot accounts being registered for the crypto spam campaign started overwhelming the servers that handle new signups at Mastodon.social.

“We suddenly went from like three registrations per minute to 900 a minute,” Chaput said. “There was nothing in the Mastodon software to detect that activity, and the protocol is not designed to handle this.”

Seeking to gain a temporary handle on the spam wave, Chaput said he briefly disabled new account registrations on mastodon.social and mastondon.online. Shortly after that, those same servers came under a sustained distributed denial-of-service (DDoS) attack.

Chaput said whoever was behind the DDoS was definitely not using point-and-click DDoS tools, like a booter or stresser service.

“This was three hours non-stop, 200,000 to 400,000 requests per second,” Chaput said of the DDoS. “At first, they were targeting one path, and when we blocked that they started to randomize things. Over three hours the attack evolved several times.”

Chaput says the spam waves have died down since they retrofitted mastodon.social with a CAPTCHA, those squiggly letter and number combinations designed to stymie automated account creation tools. But he’s worried that other Mastodon instances may not be as well-staffed and might be easy prey for these spammers.

“We don’t know if this is the work of one person, or if this is [related to] software or services being sold to others,” Chaput told KrebsOnSecurity. “We’re really impressed by the scale of it — using hundreds of domains and thousands of Microsoft email addresses.”

Chaput said a review of their logs indicates many of the newly registered Mastodon spam accounts were registered using the same 0auth credentials, and that a domain common to those credentials was quot[.]pw.

A DIRECT QUOT

The domain quot[.]pw has been registered and abandoned by several parties since 2014, but the most recent registration data available through DomainTools.com shows it was registered in March 2020 to someone in Krasnodar, Russia with the email address edgard011012@gmail.com.

This email address is also connected to accounts on several Russian cybercrime forums, including “__edman__,” who had a history of selling “logs” — large amounts of data stolen from many bot-infected computers — as well as giving away access to hacked Internet of Things (IoT) devices.

In September 2018, a user by the name “ципа” (phonetically “Zipper” in Russian) registered on the Russian hacking forum Lolzteam using the edgard0111012@gmail.com address. In May 2020, Zipper told another Lolzteam member that quot[.]pw was their domain. That user advertised a service called “Quot Project” which said they could be hired to write programming scripts in Python and C++.

“I make Telegram bots and other rubbish cheaply,” reads one February 2020 sales thread from Zipper.

Clicking the “open chat in Telegram” button on Zipper’s Lolzteam profile page launched a Telegram instant message chat window where the user Quotpw responded almost immediately. Asked if they were aware their domain was being used to manage a spam botnet that was pelting Mastodon instances with crypto scam spam, Quotpw confirmed the spam was powered by their software.

“It was made for a limited circle of people,” Quotpw said, noting that they recently released the bot software as open source on GitHub.

Quotpw went on to say the spam botnet was powered by well more than the hundreds of IP addresses tracked by Chaput, and that these systems were mostly residential proxies. A residential proxy generally refers to a computer or mobile device running some type of software that enables the system to be used as a pass-through for Internet traffic from others.

Very often, this proxy software is installed surreptitiously, such as through a “Free VPN” service or mobile app. Residential proxies also can refer to households protected by compromised home routers running factory-default credentials or outdated firmware.

Quotpw maintains they have earned more than $2,000 sending roughly 100,000 private mentions to users of different Mastodon communities over the past few weeks. Quotpw said their conversion rate for the same bot-powered direct message spam on Twitter is usually much higher and more profitable, although they conceded that recent adjustments to Twitter’s anti-bot CAPTCHA have put a crimp in their Twitter earnings.

“My partners (I’m programmer) lost time and money while ArkoseLabs (funcaptcha) introduced new precautions on Twitter,” Quotpw wrote in a Telegram reply. “On Twitter, more spam and crypto scam.”

Asked whether they felt at all conflicted about spamming people with invitations to cryptocurrency scams, Quotpw said in their hometown “they pay more for such work than in ‘white’ jobs” — referring to legitimate programming jobs that don’t involve malware, botnets, spams and scams.

“Consider salaries in Russia,” Quotpw said. “Any spam is made for profit and brings illegal money to spammers.”

THE VIENNA CONNECTION

Shortly after edgard011012@gmail.com registered quot[.]pw, the WHOIS registration records for the domain were changed again, to msr-sergey2015@yandex.ru, and to a phone number in Austria: +43.6607003748.

Constella Intelligence, a company that tracks breached data, finds that the address msr-sergey2015@yandex.ru has been associated with accounts at the mobile app site aptoide.com (user: CoolappsforAndroid) and vimeworld.ru that were created from different Internet addresses in Vienna, Austria.

A search in Skype on that Austrian phone number shows it belongs to a Sergey Proshutinskiy who lists his location as Vienna, Austria. The very first result that comes up when one searches that unusual name in Google is a LinkedIn profile for a Sergey Proshutinskiy from Vienna, Austria.

Proshutinskiy’s LinkedIn profile says he is a Class of 2024 student at TGM, which is a state-owned, technical and engineering school in Austria. His resume also says he is a data science intern at Mondi Group, an Austrian manufacturer of sustainable packaging and paper.

Mr. Proshutinskiy did not respond to requests for comment.

Quotpw denied being Sergey, and said Sergey was a friend who registered the domain as a birthday present and favor last year.

“Initially, I bought it for 300 rubles,” Quotpw explained. “The extension cost 1300 rubles (expensive). I waited until it expired and forgot to buy it. After that, a friend (Sergey) bought [the] domain and transferred access rights to me.”

“He’s not even an information security specialist,” Quotpw said of Sergey. “My friends do not belong to this field. None of my friends are engaged in scams or other black [hat] activities.”

It may seem unlikely that someone would go to all this trouble to spam Mastodon users over several weeks using an impressive number of resources — all for just $2,000 in profit. But it is likely that whoever is actually running the various crypto scam platforms advertised by Quotpw’s spam messages pays handsomely for any investments generated by their spam.

According to the FBI, financial losses from cryptocurrency investment scams dwarfed losses for all other types of cybercrime in 2022, rising from $907 million in 2021 to $2.57 billion last year.

Update, May 25, 10:30 a.m.:  Corrected attribution of the Austrian school TGM.

U.S., U.K. Sanction 7 Men Tied to Trickbot Hacking Group

Authorities in the United States and United Kingdom today levied financial sanctions against seven men accused of operating “Trickbot,” a cybercrime-as-a-service platform based in Russia that has enabled countless ransomware attacks and bank account takeovers since its debut in 2016. The U.S. Department of the Treasury says the Trickbot group is associated with Russian intelligence services, and that this alliance led to the targeting of many U.S. companies and government entities.

Initially a stealthy trojan horse program delivered via email and used to steal passwords, Trickbot evolved into “a highly modular malware suite that provides the Trickbot Group with the ability to conduct a variety of illegal cyber activities, including ransomware attacks,” the Treasury Department said.

“During the height of the COVID-19 pandemic in 2020, Trickbot targeted hospitals and healthcare centers, launching a wave of ransomware attacks against hospitals across the United States,” the sanctions notice continued. “In one of these attacks, the Trickbot Group deployed ransomware against three Minnesota medical facilities, disrupting their computer networks and telephones, and causing a diversion of ambulances. Members of the Trickbot Group publicly gloated over the ease of targeting the medical facilities and the speed with which the ransoms were paid to the group.”

Only one of the men sanctioned today is known to have been criminally charged in connection with hacking activity. According to the Treasury Department, the alleged senior leader of the Trickbot group is 34-year-old Russian national Vitaly “Bentley” Kovalev.

A New Jersey grand jury indicted Kovalev in 2012 after an investigation by the U.S. Secret Service determined that he ran a massive “money mule” scheme, which used phony job offers to trick people into laundering money stolen from hacked small to mid-sized businesses in the United States. The 2012 indictment against Kovalev relates to cybercrimes he allegedly perpetrated prior to the creation of Trickbot.

BOTNET, THE MOVIE

In 2015, Kovalev reportedly began filming a movie in Russia about cybercrime called “Botnet.” According to a 2016 story from Forbes.ru, Botnet’s opening scene was to depict the plight of Christina Svechinskaya, a Russian student arrested by FBI agents in September 2010.

Svechinskaya was one of Bentley’s money mules, most of whom were young Russian students on temporary travel visas in the United States. She was among 37 alleged mules charged with aiding an international cybercrime operation — basically, setting up phony corporate bank accounts for the sole purpose of laundering stolen funds.

Although she possessed no real hacking skills, Svechinskaya’s mugshot and social media photos went viral online and she was quickly dubbed “the world’s sexiest computer hacker” by the tabloids.

Kovalev’s Botnet film project was disrupted after Russian authorities raided the film production company’s offices as part of a cybercrime investigation. In February 2016, Reuters reported that the raid was connected to a crackdown on “Dyre,” a sophisticated trojan that U.S. federal investigators say was the precursor to the Trickbot malware. The Forbes.ru article cited sources close to the investigation who said the film studio was operating as a money-laundering front for the cybercrooks behind Dyre.

TREASON

But shifting political winds in Russia would soon bring high treason charges against three of the Russian cybercrime investigators tied to the investigation into the film studio. In a major shakeup in 2017, the Kremlin levied treason charges against Sergey Mikhaylov, then deputy chief of Russia’s top anti-cybercrime unit.

Also charged with treason was Ruslan Stoyanov, then a senior employee at Russian security firm Kaspersky Lab [the Forbes.ru report from 2016 said investigators from Mikhaylov’s unit and Kaspersky Lab were present at the film company raid].

Russian media outlets have speculated that the men were accused of treason for helping American cybercrime investigators pursue top Russian hackers. However, the charges against both men were classified and have never been officially revealed. After their brief, closed trial, both men were convicted of treason. Mikhaylov was given a 22 year prison sentence; Stoyanov was sentenced to 14 years in prison.

In September 2021, the Kremlin issued treason charges against Ilya Sachkov, formerly head of the cybersecurity firm Group-IB. According to Reuters, Sachkov and his company were hired by the film studio “to advise the Botnet director and writers on the finer points of cybercrime.” Sachkov remains imprisoned in Russia pending his treason trial.

A WELL-OILED CYBERCRIME MACHINE

Trickbot was heavily used by Conti and Ryuk, two of Russia’s most ruthless and successful ransomware groups. Blockchain analysis firm Chainalysis estimates that in 2021 alone, Conti extorted more than USD $100 million from its hacking victims; Chainalysis estimates Ryuk extorted more than USD $150 million from its ransomware victims.

The U.S. cybersecurity firm CrowdStrike has long tracked the activities of Trickbot, Ryuk and Conti under the same moniker — “Wizard Spider” — which CrowdStrike describes as “a Russia-nexus cybercriminal group behind the core development and distribution of a sophisticated arsenal of criminal tools, that allow them to run multiple different types of operations.”

“CrowdStrike Intelligence has observed WIZARD SPIDER targeting multiple countries and industries such as academia, energy, financial services, government, and more,” said Adam Meyers, head of intelligence at CrowdStrike.

This is not the U.S. government’s first swipe at the Trickbot group. In early October 2020, KrebsOnSecurity broke the news that someone had launched a series of coordinated attacks designed to disrupt the Trickbot botnet. A week later, The Washington Post ran a story saying the attack on Trickbot was the work of U.S. Cyber Command, a branch of the Department of Defense headed by the director of the U.S. National Security Agency (NSA).

Days after Russia invaded Ukraine in February 2022, a Ukrainian researcher leaked several years of internal chat logs from the Conti ransomware gang. Those candid conversations offer a fascinating view into the challenges of running a sprawling criminal enterprise with more than 100 salaried employees. They also showed that Conti enjoyed protection from prosecution by Russian authorities, as long as the hacker group took care not to target Russian organizations.

In addition, the leaked Conti chats confirmed there was considerable overlap in the operation and leadership of Conti, Trickbot and Ryuk.

Michael DeBolt, chief intelligence officer at cybersecurity firm Intel 471, said the leaked Conti chats showed Bentley oversaw a team of coders tasked with ensuring that the Trickbot and Conti malware remained undetected by the different antivirus and security software vendors.

In the years prior to the emergence of Trickbot in 2016, Bentley worked closely on the Gameover ZeuS trojan, a peer-to-peer malware threat that infected between 500,000 and a million computers with an automated ransomware strain called Cryptolocker, DeBolt said.

The FBI has a standing $3 million bounty offered for the capture of Evgeny “Slavik” Bogachev, the alleged author of the Zeus trojan. And there are indications that Bentley worked directly with Bogachev. DeBolt pointed to an October 2014 discussion on the exclusive Russian hacking forum Mazafaka that included a complaint by a Russian hosting firm against a forum user by the name “Ferrari” who had failed to pay a $30,000 hosting bill.

In that discussion thread, it emerged that the hosting company thought it was filing a complaint against Slavik. But the Mazafaka member who vouched for Ferrari’s membership on the forum said they knew Ferrari as Bentley the mule handler, and at some point Slavik and Bentley must have been sharing the Ferrari user account.

“It is likely that Slavik (aka. Bogachev) and Bentley (aka. Kovalev) shared the same ‘Ferrari’ handle on the Mazafaka forum circa 2014, which suggests the two had a working relationship at that time, and supports the recent US and UK Government announcements regarding Kovalev’s past involvement in cybercrime predating Dyre or the Trickbot Group,” DeBolt said.

CrowdStrike’s Meyers said while Wizard Spider operations have significantly reduced following the demise of Conti in June 2022, today’s sanctions will likely cause temporary disruptions for the cybercriminal group while they look for ways to circumvent the financial restrictions — which make it illegal to transact with or hold the assets of sanctioned persons or entities.

“Often, when cybercriminal groups are disrupted, they will go dark for a time only to rebrand under a new name,” Meyers said.

The prosecution of Kovalev is being handled by the U.S. Attorney’s Office in New Jersey. A copy of the now-unsealed 2012 indictment of Kovalev is here (PDF).