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There are indications that U.S. healthcare giant Change Healthcare has made a $22 million extortion payment to the infamous BlackCat ransomware group (a.k.a. “ALPHV“) as the company struggles to bring services back online amid a cyberattack that has disrupted prescription drug services nationwide for weeks. However, the cybercriminal who claims to have given BlackCat access to Change’s network says the crime gang cheated them out of their share of the ransom, and that they still have the sensitive data Change reportedly paid the group to destroy. Meanwhile, the affiliate’s disclosure appears to have prompted BlackCat to cease operations entirely.
Image: Varonis.
In the third week of February, a cyber intrusion at Change Healthcare began shutting down important healthcare services as company systems were taken offline. It soon emerged that BlackCat was behind the attack, which has disrupted the delivery of prescription drugs for hospitals and pharmacies nationwide for nearly two weeks.
On March 1, a cryptocurrency address that security researchers had already mapped to BlackCat received a single transaction worth approximately $22 million. On March 3, a BlackCat affiliate posted a complaint to the exclusive Russian-language ransomware forum Ramp saying that Change Healthcare had paid a $22 million ransom for a decryption key, and to prevent four terabytes of stolen data from being published online.
The affiliate claimed BlackCat/ALPHV took the $22 million payment but never paid him his percentage of the ransom. BlackCat is known as a “ransomware-as-service” collective, meaning they rely on freelancers or affiliates to infect new networks with their ransomware. And those affiliates in turn earn commissions ranging from 60 to 90 percent of any ransom amount paid.
“But after receiving the payment ALPHV team decide to suspend our account and keep lying and delaying when we contacted ALPHV admin,” the affiliate “Notchy” wrote. “Sadly for Change Healthcare, their data [is] still with us.”
Change Healthcare has neither confirmed nor denied paying, and has responded to multiple media outlets with a similar non-denial statement — that the company is focused on its investigation and on restoring services.
Assuming Change Healthcare did pay to keep their data from being published, that strategy seems to have gone awry: Notchy said the list of affected Change Healthcare partners they’d stolen sensitive data from included Medicare and a host of other major insurance and pharmacy networks.
On the bright side, Notchy’s complaint seems to have been the final nail in the coffin for the BlackCat ransomware group, which was infiltrated by the FBI and foreign law enforcement partners in late December 2023. As part of that action, the government seized the BlackCat website and released a decryption tool to help victims recover their systems.
BlackCat responded by re-forming, and increasing affiliate commissions to as much as 90 percent. The ransomware group also declared it was formally removing any restrictions or discouragement against targeting hospitals and healthcare providers.
However, instead of responding that they would compensate and placate Notchy, a representative for BlackCat said today the group was shutting down and that it had already found a buyer for its ransomware source code.
The seizure notice now displayed on the BlackCat darknet website.
“There’s no sense in making excuses,” wrote the RAMP member “Ransom.” “Yes, we knew about the problem, and we were trying to solve it. We told the affiliate to wait. We could send you our private chat logs where we are shocked by everything that’s happening and are trying to solve the issue with the transactions by using a higher fee, but there’s no sense in doing that because we decided to fully close the project. We can officially state that we got screwed by the feds.”
BlackCat’s website now features a seizure notice from the FBI, but several researchers noted that this image seems to have been merely cut and pasted from the notice the FBI left in its December raid of BlackCat’s network. The FBI has not responded to requests for comment.
Fabian Wosar, head of ransomware research at the security firm Emsisoft, said it appears BlackCat leaders are trying to pull an “exit scam” on affiliates by withholding many ransomware payment commissions at once and shutting down the service.
“ALPHV/BlackCat did not get seized,” Wosar wrote on Twitter/X today. “They are exit scamming their affiliates. It is blatantly obvious when you check the source code of their new takedown notice.”
Dmitry Smilyanets, a researcher for the security firm Recorded Future, said BlackCat’s exit scam was especially dangerous because the affiliate still has all the stolen data, and could still demand additional payment or leak the information on his own.
“The affiliates still have this data, and they’re mad they didn’t receive this money, Smilyanets told Wired.com. “It’s a good lesson for everyone. You cannot trust criminals; their word is worth nothing.”
BlackCat’s apparent demise comes closely on the heels of the implosion of another major ransomware group — LockBit, a ransomware gang estimated to have extorted over $120 million in payments from more than 2,000 victims worldwide. On Feb. 20, LockBit’s website was seized by the FBI and the U.K.’s National Crime Agency (NCA) following a months-long infiltration of the group.
LockBit also tried to restore its reputation on the cybercrime forums by resurrecting itself at a new darknet website, and by threatening to release data from a number of major companies that were hacked by the group in the weeks and days prior to the FBI takedown.
But LockBit appears to have since lost any credibility the group may have once had. After a much-promoted attack on the government of Fulton County, Ga., for example, LockBit threatened to release Fulton County’s data unless paid a ransom by Feb. 29. But when Feb. 29 rolled around, LockBit simply deleted the entry for Fulton County from its site, along with those of several financial organizations that had previously been extorted by the group.
Fulton County held a press conference to say that it had not paid a ransom to LockBit, nor had anyone done so on their behalf, and that they were just as mystified as everyone else as to why LockBit never followed through on its threat to publish the county’s data. Experts told KrebsOnSecurity LockBit likely balked because it was bluffing, and that the FBI likely relieved them of that data in their raid.
Smilyanets’ comments are driven home in revelations first published last month by Recorded Future, which quoted an NCA official as saying LockBit never deleted the data after being paid a ransom, even though that is the only reason many of its victims paid.
“If we do not give you decrypters, or we do not delete your data after payment, then nobody will pay us in the future,” LockBit’s extortion notes typically read.
Hopefully, more companies are starting to get the memo that paying cybercrooks to delete stolen data is a losing proposition all around.
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:
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.”
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