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Before yesterdayKrebs on Security

New Ransom Payment Schemes Target Executives, Telemedicine

By BrianKrebs

Ransomware groups are constantly devising new methods for infecting victims and convincing them to pay up, but a couple of strategies tested recently seem especially devious. The first centers on targeting healthcare organizations that offer consultations over the Internet and sending them booby-trapped medical records for the “patient.” The other involves carefully editing email inboxes of public company executives to make it appear that some were involved in insider trading.

Alex Holden is founder of Hold Security, a Milwaukee-based cybersecurity firm. Holden’s team gained visibility into discussions among members of two different ransom groups: CLOP (a.k.a. “Cl0p” a.k.a. “TA505“), and a newer ransom group known as Venus.

Last month, the U.S. Department of Health and Human Services (HHS) warned that Venus ransomware attacks were targeting a number of U.S. healthcare organizations. First spotted in mid-August 2022, Venus is known for hacking into victims’ publicly-exposed Remote Desktop services to encrypt Windows devices.

Holden said the internal discussions among the Venus group members indicate this gang has no problem gaining access to victim organizations.

“The Venus group has problems getting paid,” Holden said. “They are targeting a lot of U.S. companies, but nobody wants to pay them.”

Which might explain why their latest scheme centers on trying to frame executives at public companies for insider trading charges. Venus indicated it recently had success with a method that involves carefully editing one or more email inbox files at a victim firm — to insert messages discussing plans to trade large volumes of the company’s stock based on non-public information.

“We imitate correspondence of the [CEO] with a certain insider who shares financial reports of his companies through which your victim allegedly trades in the stock market, which naturally is a criminal offense and — according to US federal laws [includes the possibility of up to] 20 years in prison,” one Venus member wrote to an underling.

“You need to create this file and inject into the machine(s) like this so that metadata would say that they were created on his computer,” they continued. “One of my clients did it, I don’t know how. In addition to pst, you need to decompose several files into different places, so that metadata says the files are native from a certain date and time rather than created yesterday on an unknown machine.”

Holden said it’s not easy to plant emails into an inbox, but it can be done with Microsoft Outlook .pst files, which the attackers may also have access to if they’d already compromised a victim network.

“It’s not going to be forensically solid, but that’s not what they care about,” he said. “It still has the potential to be a huge scandal — at least for a while — when a victim is being threatened with the publication or release of these records.”

The Venus ransom group’s extortion note. Image: Tripwire.com

Holden said the CLOP ransomware gang has a different problem of late: Not enough victims. The intercepted CLOP communication seen by KrebsOnSecurity shows the group bragged about twice having success infiltrating new victims in the healthcare industry by sending them infected files disguised as ultrasound images or other medical documents for a patient seeking a remote consultation.

The CLOP members said one tried-and-true method of infecting healthcare providers involved gathering healthcare insurance and payment data to use in submitting requests for a remote consultation on a patient who has cirrhosis of the liver.

“Basically, they’re counting on doctors or nurses reviewing the patient’s chart and scans just before the appointment,” Holden said. “They initially discussed going in with cardiovascular issues, but decided cirrhosis or fibrosis of the liver would be more likely to be diagnosable remotely from existing test results and scans.”

While CLOP as a money making collective is a fairly young organization, security experts say CLOP members hail from a group of Threat Actors (TA) known as “TA505,” which MITRE’s ATT&CK database says is a financially motivated cybercrime group that has been active since at least 2014. “This group is known for frequently changing malware and driving global trends in criminal malware distribution,” MITRE assessed.

In April, 2021, KrebsOnSecurity detailed how CLOP helped pioneer another innovation aimed at pushing more victims into paying an extortion demand: Emailing the ransomware victim’s customers and partners directly and warning that their data would be leaked to the dark web unless they can convince the victim firm to pay up.

Security firm Tripwire points out that the HHS advisory on Venus says multiple threat actor groups are likely distributing the Venus ransomware. Tripwire’s tips for all organizations on avoiding ransomware attacks include:

  • Making secure offsite backups.
  • Running up-to-date security solutions and ensuring that your computers are protected with the latest security patches against vulnerabilities.
  • Using hard-to-crack unique passwords to protect sensitive data and accounts, as well as enabling multi-factor authentication.
  • Encrypting sensitive data wherever possible.
  • Continuously educating and informing staff about the risks and methods used by cybercriminals to launch attacks and steal data.

While the above tips are important and useful, one critical area of ransomware preparedness overlooked by too many organizations is the need to develop — and then periodically rehearse — a plan for how everyone in the organization should respond in the event of a ransomware or data ransom incident. Drilling this breach response plan is key because it helps expose weaknesses in those plans that could be exploited by the intruders.

As noted in last year’s story Don’t Wanna Pay Ransom Gangs? Test Your Backups, experts say the biggest reason ransomware targets and/or their insurance providers still pay when they already have reliable backups of their systems and data is that nobody at the victim organization bothered to test in advance how long this data restoration process might take.

“Suddenly the victim notices they have a couple of petabytes of data to restore over the Internet, and they realize that even with their fast connections it’s going to take three months to download all these backup files,” said Fabian Wosar, chief technology officer at Emsisoft. “A lot of IT teams never actually make even a back-of-the-napkin calculation of how long it would take them to restore from a data rate perspective.”

Researchers Quietly Cracked Zeppelin Ransomware Keys

By BrianKrebs

Peter is an IT manager for a technology manufacturer that got hit with a Russian ransomware strain called “Zeppelin” in May 2020. He’d been on the job less than six months, and because of the way his predecessor architected things, the company’s data backups also were encrypted by Zeppelin. After two weeks of stalling their extortionists, Peter’s bosses were ready to capitulate and pay the ransom demand. Then came the unlikely call from an FBI agent. “Don’t pay,” the agent said. “We’ve found someone who can crack the encryption.”

Peter, who spoke candidly about the attack on condition of anonymity, said the FBI told him to contact a cybersecurity consulting firm in New Jersey called Unit 221B, and specifically its founder — Lance James. Zeppelin sprang onto the crimeware scene in December 2019, but it wasn’t long before James discovered multiple vulnerabilities in the malware’s encryption routines that allowed him to brute-force the decryption keys in a matter of hours, using nearly 100 cloud computer servers.

In an interview with KrebsOnSecurity, James said Unit 221B was wary of advertising its ability to crack Zeppelin ransomware keys because it didn’t want to tip its hand to Zeppelin’s creators, who were likely to modify their file encryption approach if they detected it was somehow being bypassed.

This is not an idle concern. There are multiple examples of ransomware groups doing just that after security researchers crowed about finding vulnerabilities in their ransomware code.

“The minute you announce you’ve got a decryptor for some ransomware, they change up the code,” James said.

But he said the Zeppelin group appears to have stopped spreading their ransomware code gradually over the past year, possibly because Unit 221B’s referrals from the FBI let them quietly help nearly two dozen victim organizations recover without paying their extortionists.

In a blog post published today to coincide with a Black Hat talk on their discoveries, James and co-author Joel Lathrop said they were motivated to crack Zeppelin after the ransomware gang started attacking nonprofit and charity organizations.

“What motivated us the most during the leadup to our action was the targeting of homeless shelters, nonprofits and charity organizations,” the two wrote. “These senseless acts of targeting those who are unable to respond are the motivation for this research, analysis, tools, and blog post. A general Unit 221B rule of thumb around our offices is: Don’t [REDACTED] with the homeless or sick! It will simply trigger our ADHD and we will get into that hyper-focus mode that is good if you’re a good guy, but not so great if you are an ***hole.”

The researchers said their break came when they understood that while Zeppelin used three different types of encryption keys to encrypt files, they could undo the whole scheme by factoring or computing just one of them: An ephemeral RSA-512 public key that is randomly generated on each machine it infects.

“If we can recover the RSA-512 Public Key from the registry, we can crack it and get the 256-bit AES Key that encrypts the files!” they wrote. “The challenge was that they delete the [public key] once the files are fully encrypted. Memory analysis gave us about a 5-minute window after files were encrypted to retrieve this public key.”

Unit 221B ultimately built a “Live CD” version of Linux that victims could run on infected systems to extract that RSA-512 key. From there, they would load the keys into a cluster of 800 CPUs donated by hosting giant Digital Ocean that would then start cracking them. The company also used that same donated infrastructure to help victims decrypt their data using the recovered keys.

A typical Zeppelin ransomware note.

Jon is another grateful Zeppelin ransomware victim who was aided by Unit 221B’s decryption efforts. Like Peter, Jon asked that his last name and that of his employer be omitted from the story, but he’s in charge of IT for a mid-sized managed service provider that got hit with Zeppelin in July 2020.

The attackers that savaged Jon’s company managed to phish credentials and a multi-factor authentication token for some tools the company used to support customers, and in short order they’d seized control over the servers and backups for a healthcare provider customer.

Jon said his company was reluctant to pay a ransom in part because it wasn’t clear from the hackers’ demands whether the ransom amount they demanded would provide a key to unlock all systems, and that it would do so safely.

“They want you to unlock your data with their software, but you can’t trust that,” Jon said. “You want to use your own software or someone else who’s trusted to do it.”

In August 2022, the FBI and the Cybersecurity & Infrastructure Security Agency (CISA) issued a joint warning on Zeppelin, saying the FBI had “observed instances where Zeppelin actors executed their malware multiple times within a victim’s network, resulting in the creation of different IDs or file extensions, for each instance of an attack; this results in the victim needing several unique decryption keys.”

The advisory says Zeppelin has attacked “a range of businesses and critical infrastructure organizations, including defense contractors, educational institutions, manufacturers, technology companies, and especially organizations in the healthcare and medical industries. Zeppelin actors have been known to request ransom payments in Bitcoin, with initial amounts ranging from several thousand dollars to over a million dollars.”

The FBI and CISA say the Zeppelin actors gain access to victim networks by exploiting weak Remote Desktop Protocol (RDP) credentials, exploiting SonicWall firewall vulnerabilities, and phishing campaigns. Prior to deploying Zeppelin ransomware, actors spend one to two weeks mapping or enumerating the victim network to identify data enclaves, including cloud storage and network backups, the alert notes.

Jon said he felt so lucky after connecting with James and hearing about their decryption work, that he toyed with the idea of buying a lottery ticket that day.

“This just doesn’t usually happen,” Jon said. “It’s 100 percent like winning the lottery.”

By the time Jon’s company got around to decrypting their data, they were forced by regulators to prove that no patient data had been exfiltrated from their systems. All told, it took his employer two months to fully recover from the attack.

“I definitely feel like I was ill-prepared for this attack,” Jon said. “One of the things I’ve learned from this is the importance of forming your core team and having those people who know what their roles and responsibilities are ahead of time. Also, trying to vet new vendors you’ve never met before and build trust relationships with them is very difficult to do when you have customers down hard now and they’re waiting on you to help them get back up.”

A more technical writeup on Unit 221B’s discoveries (cheekily titled “0XDEAD ZEPPELIN”) is available here.

Hacker Charged With Extorting Online Psychotherapy Service

By BrianKrebs

A 25-year-old Finnish man has been charged with extorting a once popular and now-bankrupt online psychotherapy company and its patients. Finnish authorities rarely name suspects in an investigation, but they were willing to make an exception for Julius “Zeekill” Kivimaki, a notorious hacker who — at the tender age of 17 — had been convicted of more than 50,000 cybercrimes, including data breaches, payment fraud, operating botnets, and calling in bomb threats.

In late October 2022, Kivimaki was charged (and arrested in absentia, according to the Finns) with attempting to extort money from the Vastaamo Psychotherapy Center.  On October 21, 2020, Vastaamo became the target of blackmail when a tormentor identified as “ransom_man” demanded payment of 40 bitcoins (~450,000 euros at the time) in return for a promise not to publish highly sensitive therapy session notes Vastaamo had exposed online.

In a series of posts over the ensuing days on a Finnish-language dark net discussion board, ransom_man said Vastaamo appeared unwilling to negotiate a payment, and that he would start publishing 100 patient profiles every 24 hours “to provide further incentive for the company to continue communicating with us.”

“We’re not asking for much, approximately 450,000 euros which is less than 10 euros per patient and only a small fraction of the around 20 million yearly revenues of this company,” ransom_man wrote.

When Vastaamo declined to pay, ransom_man shifted to extorting individual patients. According to Finnish police, some 22,000 victims reported extortion attempts targeting them personally, targeted emails that threatened to publish their therapy notes online unless paid a 500 euro ransom.

The extortion message targeted Vastaamo patients.

On Oct. 23, 2020, ransom_man uploaded to the dark web a large compressed file that included all of the stolen Vastaamo patient records. But investigators found the file also contained an entire copy of ransom_man’s home folder, a likely mistake that exposed a number of clues that they say point to Kivimaki.

Ransom_man quickly deleted the large file (accompanied by a “whoops” notation), but not before it had been downloaded a number of times. The entire archive has since been made into a searchable website on the Dark Web.

Among those who grabbed a copy of the database was Antti Kurittu, a team lead at Nixu Corporation and a former criminal investigator. In 2013, Kurittu worked on investigation involving Kivimaki’s use of the Zbot botnet, among other activities Kivimaki engaged in as a member of the hacker group Hack the Planet.

“It was a huge opsec [operational security] fail, because they had a lot of stuff in there — including the user’s private SSH folder, and a lot of known hosts that we could take a very good look at,” Kurittu told KrebsOnSecurity, declining to discuss specifics of the evidence investigators seized. “There were also other projects and databases.”

Kurittu said he and others he and others who were familiar with illegal activities attributed to Kivimäki couldn’t shake suspicion that the infamous cybercriminal was also behind the Vastaamo extortion.

“I couldn’t find anything that would link that data directly to one individual, but there were enough indicators in there that put the name in my head and I couldn’t shake it,” Kurittu said. “When they named him as the prime suspect I was not surprised.”

A handful of individually extorted victims paid a ransom, but when news broke that the entire Vastaamo database had been leaked online, the extortion threats no longer held their sting. However, someone would soon set up a site on the dark web where anyone could search this sensitive data.

Kivimaki stopped using his middle name Julius in favor of his given first name Aleksanteri when he moved abroad several years ago. A Twitter account by that name was verified by Kivimaki’s attorney as his, and through that account he denied being involved in the Vastaamo extortion.

“I believe [the Finnish authorities] brought this to the public in order to influence the decision-making of my old case from my teenage years, which was just processed in the Court of Appeal, both cases are investigated by the same persons,” Kivimaki tweeted on Oct. 28.

Kivimaki is appealing a 2020 district court decision sentencing him to “one year of conditional imprisonment for two counts of fraud committed as a young person, and one of gross fraud, interference with telecommunications as a young person, aggravated data breach as a young person and incitement to fraud as a young person,” according to the Finnish tabloid Ilta-Sanomat.

“Now in the Court of Appeal, the prosecutor is demanding a harsher punishment for the man, i.e. unconditional imprisonment,” reads the Ilta-Sanomat story. “The prosecutor notes in his complaint that the young man has been committing cybercrimes from Espoo since he was 15 years old, and the actions have had to be painstakingly investigated through international legal aid.”

As described in this Wired story last year, Vastaamo filled an urgent demand for psychological counseling, and it won accolades from Finnish health authorities and others for its services.

“Vastaamo was a private company, but it seemed to operate in the same spirit of tech-enabled ease and accessibility: You booked a therapist with a few clicks, wait times were tolerable, and Finland’s Social Insurance Institution reimbursed a big chunk of the session fee (provided you had a diagnosed mental disorder),” William Ralston wrote for Wired. “The company was run by Ville Tapio, a 39-year-old coder and entrepreneur with sharp eyebrows, slicked-back brown hair, and a heavy jawline. He’d cofounded the company with his parents. They pitched ­Vastaamo as a humble family-run enterprise committed to improving the mental health of all Finns.”

But for all the good it brought, the healthcare records management system that Vastaamo used relied on little more than a MySQL database that was left dangerously exposed to the web for 16 months, guarded by nothing more than an administrator account with a blank password.

The Finnish daily Iltalehti said Tapio was relieved of his duties as CEO of Vastaamo in October 2020, and that in September, prosecutors brought charges against Tapio for a data protection offense in connection with Vastaamo’s information leak.

“According to Vastaamo, the data breach in Vastaamo’s customer databases took place in November 2018,” Iltalehti reported last month. “According to Vastaamo, Tapio concealed information about the data breach for more than a year and a half.”

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