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Thread hijacking attacks. They happen when someone you know has their email account compromised, and you are suddenly dropped into an existing conversation between the sender and someone else. These missives draw on the recipient’s natural curiosity about being copied on a private discussion, which is modified to include a malicious link or attachment. Here’s the story of a thread hijacking attack in which a journalist was copied on a phishing email from the unwilling subject of a recent scoop.
In Sept. 2023, the Pennsylvania news outlet LancasterOnline.com published a story about Adam Kidan, a wealthy businessman with a criminal past who is a major donor to Republican causes and candidates, including Rep. Lloyd Smucker (R-Pa).
The LancasterOnline story about Adam Kidan.
Several months after that piece ran, the story’s author Brett Sholtis received two emails from Kidan, both of which contained attachments. One of the messages appeared to be a lengthy conversation between Kidan and a colleague, with the subject line, “Re: Successfully sent data.” The second missive was a more brief email from Kidan with the subject, “Acknowledge New Work Order,” and a message that read simply, “Please find the attached.”
Sholtis said he clicked the attachment in one of the messages, which then launched a web page that looked exactly like a Microsoft Office 365 login page. An analysis of the webpage reveals it would check any submitted credentials at the real Microsoft website, and return an error if the user entered bogus account information. A successful login would record the submitted credentials and forward the victim to the real Microsoft website.
But Sholtis said he didn’t enter his Outlook username and password. Instead, he forwarded the messages to LancasterOneline’s IT team, which quickly flagged them as phishing attempts.
LancasterOnline Executive Editor Tom Murse said the two phishing messages from Mr. Kidan raised eyebrows in the newsroom because Kidan had threatened to sue the news outlet multiple times over Sholtis’s story.
“We were just perplexed,” Murse said. “It seemed to be a phishing attempt but we were confused why it would come from a prominent businessman we’ve written about. Our initial response was confusion, but we didn’t know what else to do with it other than to send it to the FBI.”
The phishing lure attached to the thread hijacking email from Mr. Kidan.
In 2006, Kidan was sentenced to 70 months in federal prison after pleading guilty to defrauding lenders along with Jack Abramoff, the disgraced lobbyist whose corruption became a symbol of the excesses of Washington influence peddling. He was paroled in 2009, and in 2014 moved his family to a home in Lancaster County, Pa.
The FBI hasn’t responded to LancasterOnline’s tip. Messages sent by KrebsOnSecurity to Kidan’s emails addresses were returned as blocked. Messages left with Mr. Kidan’s company, Empire Workforce Solutions, went unreturned.
No doubt the FBI saw the messages from Kidan for what they likely were: The result of Mr. Kidan having his Microsoft Outlook account compromised and used to send malicious email to people in his contacts list.
Thread hijacking attacks are hardly new, but that is mainly true because many Internet users still don’t know how to identify them. The email security firm Proofpoint says it has tracked north of 90 million malicious messages in the last five years that leverage this attack method.
One key reason thread hijacking is so successful is that these attacks generally do not include the tell that exposes most phishing scams: A fabricated sense of urgency. A majority of phishing threats warn of negative consequences should you fail to act quickly — such as an account suspension or an unauthorized high-dollar charge going through.
In contrast, thread hijacking campaigns tend to patiently prey on the natural curiosity of the recipient.
Ryan Kalember, chief strategy officer at Proofpoint, said probably the most ubiquitous examples of thread hijacking are “CEO fraud” or “business email compromise” scams, wherein employees are tricked by an email from a senior executive into wiring millions of dollars to fraudsters overseas.
But Kalember said these low-tech attacks can nevertheless be quite effective because they tend to catch people off-guard.
“It works because you feel like you’re suddenly included in an important conversation,” Kalember said. “It just registers a lot differently when people start reading, because you think you’re observing a private conversation between two different people.”
Some thread hijacking attacks actually involve multiple threat actors who are actively conversing while copying — but not addressing — the recipient.
“We call these multi-persona phishing scams, and they’re often paired with thread hijacking,” Kalember said. “It’s basically a way to build a little more affinity than just copying people on an email. And the longer the conversation goes on, the higher their success rate seems to be because some people start replying to the thread [and participating] psycho-socially.”
The best advice to sidestep phishing scams is to avoid clicking on links or attachments that arrive unbidden in emails, text messages and other mediums. If you’re unsure whether the message is legitimate, take a deep breath and visit the site or service in question manually — ideally, using a browser bookmark so as to avoid potential typosquatting sites.
In my last blog, I shared the progress we’re making toward building the Cisco Security Cloud, an open, integrated security platform capable of tackling the rigors of securing highly distributed, m… Read more on Cisco Blogs
Several Apple customers recently reported being targeted in elaborate phishing attacks that involve what appears to be a bug in Apple’s password reset feature. In this scenario, a target’s Apple devices are forced to display dozens of system-level prompts that prevent the devices from being used until the recipient responds “Allow” or “Don’t Allow” to each prompt. Assuming the user manages not to fat-finger the wrong button on the umpteenth password reset request, the scammers will then call the victim while spoofing Apple support in the caller ID, saying the user’s account is under attack and that Apple support needs to “verify” a one-time code.
Some of the many notifications Patel says he received from Apple all at once.
Parth Patel is an entrepreneur who is trying to build a startup in the conversational AI space. On March 23, Patel documented on Twitter/X a recent phishing campaign targeting him that involved what’s known as a “push bombing” or “MFA fatigue” attack, wherein the phishers abuse a feature or weakness of a multi-factor authentication (MFA) system in a way that inundates the target’s device(s) with alerts to approve a password change or login.
“All of my devices started blowing up, my watch, laptop and phone,” Patel told KrebsOnSecurity. “It was like this system notification from Apple to approve [a reset of the account password], but I couldn’t do anything else with my phone. I had to go through and decline like 100-plus notifications.”
Some people confronted with such a deluge may eventually click “Allow” to the incessant password reset prompts — just so they can use their phone again. Others may inadvertently approve one of these prompts, which will also appear on a user’s Apple watch if they have one.
But the attackers in this campaign had an ace up their sleeves: Patel said after denying all of the password reset prompts from Apple, he received a call on his iPhone that said it was from Apple Support (the number displayed was 1-800-275-2273, Apple’s real customer support line).
“I pick up the phone and I’m super suspicious,” Patel recalled. “So I ask them if they can verify some information about me, and after hearing some aggressive typing on his end he gives me all this information about me and it’s totally accurate.”
All of it, that is, except his real name. Patel said when he asked the fake Apple support rep to validate the name they had on file for the Apple account, the caller gave a name that was not his but rather one that Patel has only seen in background reports about him that are for sale at a people-search website called PeopleDataLabs.
Patel said he has worked fairly hard to remove his information from multiple people-search websites, and he found PeopleDataLabs uniquely and consistently listed this inaccurate name as an alias on his consumer profile.
“For some reason, PeopleDataLabs has three profiles that come up when you search for my info, and two of them are mine but one is an elementary school teacher from the midwest,” Patel said. “I asked them to verify my name and they said Anthony.”
Patel said the goal of the voice phishers is to trigger an Apple ID reset code to be sent to the user’s device, which is a text message that includes a one-time password. If the user supplies that one-time code, the attackers can then reset the password on the account and lock the user out. They can also then remotely wipe all of the user’s Apple devices.
Chris is a cryptocurrency hedge fund owner who asked that only his first name be used so as not to paint a bigger target on himself. Chris told KrebsOnSecurity he experienced a remarkably similar phishing attempt in late February.
“The first alert I got I hit ‘Don’t Allow’, but then right after that I got like 30 more notifications in a row,” Chris said. “I figured maybe I sat on my phone weird, or was accidentally pushing some button that was causing these, and so I just denied them all.”
Chris says the attackers persisted hitting his devices with the reset notifications for several days after that, and at one point he received a call on his iPhone that said it was from Apple support.
“I said I would call them back and hung up,” Chris said, demonstrating the proper response to such unbidden solicitations. “When I called back to the real Apple, they couldn’t say whether anyone had been in a support call with me just then. They just said Apple states very clearly that it will never initiate outbound calls to customers — unless the customer requests to be contacted.”
Massively freaking out that someone was trying to hijack his digital life, Chris said he changed his passwords and then went to an Apple store and bought a new iPhone. From there, he created a new Apple iCloud account using a brand new email address.
Chris said he then proceeded to get even more system alerts on his new iPhone and iCloud account — all the while still sitting at the local Apple Genius Bar.
Chris told KrebsOnSecurity his Genius Bar tech was mystified about the source of the alerts, but Chris said he suspects that whatever the phishers are abusing to rapidly generate these Apple system alerts requires knowing the phone number on file for the target’s Apple account. After all, that was the only aspect of Chris’s new iPhone and iCloud account that hadn’t changed.
“Ken” is a security industry veteran who spoke on condition of anonymity. Ken said he first began receiving these unsolicited system alerts on his Apple devices earlier this year, but that he has not received any phony Apple support calls as others have reported.
“This recently happened to me in the middle of the night at 12:30 a.m.,” Ken said. “And even though I have my Apple watch set to remain quiet during the time I’m usually sleeping at night, it woke me up with one of these alerts. Thank god I didn’t press ‘Allow,’ which was the first option shown on my watch. I had to scroll watch the wheel to see and press the ‘Don’t Allow’ button.”
Ken shared this photo he took of an alert on his watch that woke him up at 12:30 a.m. Ken said he had to scroll on the watch face to see the “Don’t Allow” button.
Ken didn’t know it when all this was happening (and it’s not at all obvious from the Apple prompts), but clicking “Allow” would not have allowed the attackers to change Ken’s password. Rather, clicking “Allow” displays a six digit PIN that must be entered on Ken’s device — allowing Ken to change his password. It appears that these rapid password reset prompts are being used to make a subsequent inbound phone call spoofing Apple more believable.
Ken said he contacted the real Apple support and was eventually escalated to a senior Apple engineer. The engineer assured Ken that turning on an Apple Recovery Key for his account would stop the notifications once and for all.
A recovery key is an optional security feature that Apple says “helps improve the security of your Apple ID account.” It is a randomly generated 28-character code, and when you enable a recovery key it is supposed to disable Apple’s standard account recovery process. The thing is, enabling it is not a simple process, and if you ever lose that code in addition to all of your Apple devices you will be permanently locked out.
Ken said he enabled a recovery key for his account as instructed, but that it hasn’t stopped the unbidden system alerts from appearing on all of his devices every few days.
KrebsOnSecurity tested Ken’s experience, and can confirm that enabling a recovery key does nothing to stop a password reset prompt from being sent to associated Apple devices. Visiting Apple’s “forgot password” page — https://iforgot.apple.com — asks for an email address and for the visitor to solve a CAPTCHA.
After that, the page will display the last two digits of the phone number tied to the Apple account. Filling in the missing digits and hitting submit on that form will send a system alert, whether or not the user has enabled an Apple Recovery Key.
The password reset page at iforgot.apple.com.
What sanely designed authentication system would send dozens of requests for a password change in the span of a few moments, when the first requests haven’t even been acted on by the user? Could this be the result of a bug in Apple’s systems?
Apple has not yet responded to requests for comment.
Throughout 2022, a criminal hacking group known as LAPSUS$ used MFA bombing to great effect in intrusions at Cisco, Microsoft and Uber. In response, Microsoft began enforcing “MFA number matching,” a feature that displays a series of numbers to a user attempting to log in with their credentials. These numbers must then be entered into the account owner’s Microsoft authenticator app on their mobile device to verify they are logging into the account.
Kishan Bagaria is a hobbyist security researcher and engineer who founded the website texts.com (now owned by Automattic), and he’s convinced Apple has a problem on its end. In August 2019, Bagaria reported to Apple a bug that allowed an exploit he dubbed “AirDoS” because it could be used to let an attacker infinitely spam all nearby iOS devices with a system-level prompt to share a file via AirDrop — a file-sharing capability built into Apple products.
Apple fixed that bug nearly four months later in December 2019, thanking Bagaria in the associated security bulletin. Bagaria said Apple’s fix was to add stricter rate limiting on AirDrop requests, and he suspects that someone has figured out a way to bypass Apple’s rate limit on how many of these password reset requests can be sent in a given timeframe.
“I think this could be a legit Apple rate limit bug that should be reported,” Bagaria said.
Apple seems requires a phone number to be on file for your account, but after you’ve set up the account it doesn’t have to be a mobile phone number. KrebsOnSecurity’s testing shows Apple will accept a VOIP number (like Google Voice). So, changing your account phone number to a VOIP number that isn’t widely known would be one mitigation here.
One caveat with the VOIP number idea: Unless you include a real mobile number, Apple’s iMessage and Facetime applications will be disabled for that device. This might a bonus for those concerned about reducing the overall attack surface of their Apple devices, since zero-click zero-days in these applications have repeatedly been used by spyware purveyors.
Also, it appears Apple’s password reset system will accept and respect email aliases. Adding a “+” character after the username portion of your email address — followed by a notation specific to the site you’re signing up at — lets you create an infinite number of unique email addresses tied to the same account.
For instance, if I were signing up at example.com, I might give my email address as krebsonsecurity+example@gmail.com. Then, I simply go back to my inbox and create a corresponding folder called “Example,” along with a new filter that sends any email addressed to that alias to the Example folder. In this case, however, perhaps a less obvious alias than “+apple” would be advisable.
Update, March 27, 5:06 p.m. ET: Added perspective on Ken’s experience. Also included a What Can You Do? section.
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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.
The ransomware group LockBit told officials with Fulton County, Ga. they could expect to see their internal documents published online this morning unless the county paid a ransom demand. LockBit removed Fulton County’s listing from its victim shaming website this morning, claiming the county had paid. But county officials said they did not pay, nor did anyone make payment on their behalf. Security experts say LockBit was likely bluffing and probably lost most of the data when the gang’s servers were seized this month by U.S. and U.K. law enforcement.
The LockBit website included a countdown timer until the promised release of data stolen from Fulton County, Ga. LockBit would later move this deadline up to Feb. 29, 2024.
LockBit listed Fulton County as a victim on Feb. 13, saying that unless it was paid a ransom the group would publish files stolen in a breach at the county last month. That attack disrupted county phones, Internet access and even their court system. LockBit leaked a small number of the county’s files as a teaser, which appeared to include sensitive and sealed court records in current and past criminal trials.
On Feb. 16, Fulton County’s entry — along with a countdown timer until the data would be published — was removed from the LockBit website without explanation. The leader of LockBit told KrebsOnSecurity this was because Fulton County officials had engaged in last-minute negotiations with the group.
But on Feb. 19, investigators with the FBI and the U.K.’s National Crime Agency (NCA) took over LockBit’s online infrastructure, replacing the group’s homepage with a seizure notice and links to LockBit ransomware decryption tools.
In a press briefing on Feb. 20, Fulton County Commission Chairman Robb Pitts told reporters the county did not pay a ransom demand, noting that the board “could not in good conscience use Fulton County taxpayer funds to make a payment.”
Three days later, LockBit reemerged with new domains on the dark web, and with Fulton County listed among a half-dozen other victims whose data was about to be leaked if they refused to pay. As it does with all victims, LockBit assigned Fulton County a countdown timer, saying officials had until late in the evening on March 1 until their data was published.
LockBit revised its deadline for Fulton County to Feb. 29.
LockBit soon moved up the deadline to the morning of Feb. 29. As Fulton County’s LockBit timer was counting down to zero this morning, its listing disappeared from LockBit’s site. LockBit’s leader and spokesperson, who goes by the handle “LockBitSupp,” told KrebsOnSecurity today that Fulton County’s data disappeared from their site because county officials paid a ransom.
“Fulton paid,” LockBitSupp said. When asked for evidence of payment, LockBitSupp claimed. “The proof is that we deleted their data and did not publish it.”
But at a press conference today, Fulton County Chairman Robb Pitts said the county does not know why its data was removed from LockBit’s site.
“As I stand here at 4:08 p.m., we are not aware of any data being released today so far,” Pitts said. “That does not mean the threat is over. They could release whatever data they have at any time. We have no control over that. We have not paid any ransom. Nor has any ransom been paid on our behalf.”
Brett Callow, a threat analyst with the security firm Emsisoft, said LockBit likely lost all of the victim data it stole before the FBI/NCA seizure, and that it has been trying madly since then to save face within the cybercrime community.
“I think it was a case of them trying to convince their affiliates that they were still in good shape,” Callow said of LockBit’s recent activities. “I strongly suspect this will be the end of the LockBit brand.”
Others have come to a similar conclusion. The security firm RedSense posted an analysis to Twitter/X that after the takedown, LockBit published several “new” victim profiles for companies that it had listed weeks earlier on its victim shaming site. Those victim firms — a healthcare provider and major securities lending platform — also were unceremoniously removed from LockBit’s new shaming website, despite LockBit claiming their data would be leaked.
“We are 99% sure the rest of their ‘new victims’ are also fake claims (old data for new breaches),” RedSense posted. “So the best thing for them to do would be to delete all other entries from their blog and stop defrauding honest people.”
Callow said there certainly have been plenty of cases in the past where ransomware gangs exaggerated their plunder from a victim organization. But this time feels different, he said.
“It is a bit unusual,” Callow said. “This is about trying to still affiliates’ nerves, and saying, ‘All is well, we weren’t as badly compromised as law enforcement suggested.’ But I think you’d have to be a fool to work with an organization that has been so thoroughly hacked as LockBit has.”
Malicious hackers are targeting people in the cryptocurrency space in attacks that start with a link added to the target’s calendar at Calendly, a popular application for scheduling appointments and meetings. The attackers impersonate established cryptocurrency investors and ask to schedule a video conference call. But clicking the meeting link provided by the scammers prompts the user to run a script that quietly installs malware on macOS systems.
KrebsOnSecurity recently heard from a reader who works at a startup that is seeking investment for building a new blockchain platform for the Web. The reader spoke on condition that their name not be used in this story, so for the sake of simplicity we’ll call him Doug.
Being in the cryptocurrency scene, Doug is also active on the instant messenger platform Telegram. Earlier this month, Doug was approached by someone on Telegram whose profile name, image and description said they were Ian Lee, from Signum Capital, a well-established investment firm based in Singapore. The profile also linked to Mr. Lee’s Twitter/X account, which features the same profile image.
The investor expressed interest in financially supporting Doug’s startup, and asked if Doug could find time for a video call to discuss investment prospects. Sure, Doug said, here’s my Calendly profile, book a time and we’ll do it then.
When the day and time of the scheduled meeting with Mr. Lee arrived, Doug clicked the meeting link in his calendar but nothing happened. Doug then messaged the Mr. Lee account on Telegram, who said there was some kind of technology issue with the video platform, and that their IT people suggested using a different meeting link.
Doug clicked the new link, but instead of opening up a videoconference app, a message appeared on his Mac saying the video service was experiencing technical difficulties.
“Some of our users are facing issues with our service,” the message read. “We are actively working on fixing these problems. Please refer to this script as a temporary solution.”
Doug said he ran the script, but nothing appeared to happen after that, and the videoconference application still wouldn’t start. Mr. Lee apologized for the inconvenience and said they would have to reschedule their meeting, but he never responded to any of Doug’s follow-up messages.
It didn’t dawn on Doug until days later that the missed meeting with Mr. Lee might have been a malware attack. Going back to his Telegram client to revisit the conversation, Doug discovered his potential investor had deleted the meeting link and other bits of conversation from their shared chat history.
In a post to its Twitter/X account last month, Signum Capital warned that a fake profile pretending to be their employee Mr. Lee was trying to scam people on Telegram.
The file that Doug ran is a simple Apple Script (file extension “.scpt”) that downloads and executes a malicious trojan made to run on macOS systems. Unfortunately for us, Doug freaked out after deciding he’d been tricked — backing up his important documents, changing his passwords, and then reinstalling macOS on his computer. While this a perfectly sane response, it means we don’t have the actual malware that was pushed to his Mac by the script.
But Doug does still have a copy of the malicious script that was downloaded from clicking the meeting link (the online host serving that link is now offline). A search in Google for a string of text from that script turns up a December 2023 blog post from cryptocurrency security firm SlowMist about phishing attacks on Telegram from North Korean state-sponsored hackers.
“When the project team clicks the link, they encounter a region access restriction,” SlowMist wrote. “At this point, the North Korean hackers coax the team into downloading and running a ‘location-modifying’ malicious script. Once the project team complies, their computer comes under the control of the hackers, leading to the theft of funds.”
Image: SlowMist.
SlowMist says the North Korean phishing scams used the “Add Custom Link” feature of the Calendly meeting scheduling system on event pages to insert malicious links and initiate phishing attacks.
“Since Calendly integrates well with the daily work routines of most project teams, these malicious links do not easily raise suspicion,” the blog post explains. “Consequently, the project teams may inadvertently click on these malicious links, download, and execute malicious code.”
SlowMist said the malware downloaded by the malicious link in their case comes from a North Korean hacking group dubbed “BlueNoroff, which Kaspersky Labs says is a subgroup of the Lazarus hacking group.
“A financially motivated threat actor closely connected with Lazarus that targets banks, casinos, fin-tech companies, POST software and cryptocurrency businesses, and ATMs,” Kaspersky wrote of BlueNoroff in Dec. 2023.
The North Korean regime is known to use stolen cryptocurrencies to fund its military and other state projects. A recent report from Recorded Future finds the Lazarus Group has stolen approximately $3 billion in cryptocurrency over the past six years.
While there is still far more malware out there today targeting Microsoft Windows PCs, the prevalence of information-stealing trojans aimed at macOS users is growing at a steady clip. MacOS computers include X-Protect, Apple’s built-in antivirus technology. But experts say attackers are constantly changing the appearance and behavior of their malware to evade X-Protect.
“Recent updates to macOS’s XProtect signature database indicate that Apple are aware of the problem, but early 2024 has already seen a number of stealer families evade known signatures,” security firm SentinelOne wrote in January.
According to Chris Ueland from the threat hunting platform Hunt.io, the Internet address of the fake meeting website Doug was tricked into visiting (104.168.163,149) hosts or very recently hosted about 75 different domain names, many of which invoke words associated with videoconferencing or cryptocurrency. Those domains indicate this North Korean hacking group is hiding behind a number of phony crypto firms, like the six-month-old website for Cryptowave Capital (cryptowave[.]capital).
In a statement shared with KrebsOnSecurity, Calendly said it was aware of these types of social engineering attacks by cryptocurrency hackers.
“To help prevent these kinds of attacks, our security team and partners have implemented a service to automatically detect fraud and impersonations that could lead to social engineering,” the company said. “We are also actively scanning content for all our customers to catch these types of malicious links and to prevent hackers earlier on. Additionally, we intend to add an interstitial page warning users before they’re redirected away from Calendly to other websites. Along with the steps we’ve taken, we recommend users stay vigilant by keeping their software secure with running the latest updates and verifying suspicious links through tools like VirusTotal to alert them of possible malware. We are continuously strengthening the cybersecurity of our platform to protect our customers.”
The increasing frequency of new Mac malware is a good reminder that Mac users should not depend on security software and tools to flag malicious files, which are frequently bundled with or disguised as legitimate software.
As KrebsOnSecurity has advised Windows users for years, a good rule of safety to live by is this: If you didn’t go looking for it, don’t install it. Following this mantra heads off a great deal of malware attacks, regardless of the platform used. When you do decide to install a piece of software, make sure you are downloading it from the original source, and then keep it updated with any new security fixes.
On that last front, I’ve found it’s a good idea not to wait until the last minute to configure my system before joining a scheduled videoconference call. Even if the call uses software that is already on my computer, it is often the case that software updates are required before the program can be used, and I’m one of those weird people who likes to review any changes to the software maker’s privacy policies or user agreements before choosing to install updates.
Most of all, verify new contacts from strangers before accepting anything from them. In this case, had Doug simply messaged Mr. Lee’s real account on Twitter/X or contacted Signum Capital directly, he would discovered that the real Mr. Lee never asked for a meeting.
If you’re approached in a similar scheme, the response from the would-be victim documented in the SlowMist blog post is probably the best.
Image: SlowMist.
Update: Added comment from Calendly.
The FBI’s takedown of the LockBit ransomware group last week came as LockBit was preparing to release sensitive data stolen from government computer systems in Fulton County, Ga. But LockBit is now regrouping, and the gang says it will publish the stolen Fulton County data on March 2 unless paid a ransom. LockBit claims the cache includes documents tied to the county’s ongoing criminal prosecution of former President Trump, but court watchers say teaser documents published by the crime gang suggest a total leak of the Fulton County data could put lives at risk and jeopardize a number of other criminal trials.
A new LockBit website listing a countdown timer until the promised release of data stolen from Fulton County, Ga.
In early February, Fulton County leaders acknowledged they were responding to an intrusion that caused disruptions for its phone, email and billing systems, as well as a range of county services, including court systems.
On Feb. 13, the LockBit ransomware group posted on its victim shaming blog a new entry for Fulton County, featuring a countdown timer saying the group would publish the data on Feb. 16 unless county leaders agreed to negotiate a ransom.
“We will demonstrate how local structures negligently handled information protection,” LockBit warned. “We will reveal lists of individuals responsible for confidentiality. Documents marked as confidential will be made publicly available. We will show documents related to access to the state citizens’ personal data. We aim to give maximum publicity to this situation; the documents will be of interest to many. Conscientious residents will bring order.”
Yet on Feb. 16, the entry for Fulton County was removed from LockBit’s site without explanation. This usually only happens after the victim in question agrees to pay a ransom demand and/or enters into negotiations with their extortionists.
However, Fulton County Commission Chairman Robb Pitts said the board decided it “could not in good conscience use Fulton County taxpayer funds to make a payment.”
“We did not pay nor did anyone pay on our behalf,” Pitts said at an incident briefing on Feb. 20.
Just hours before that press conference, LockBit’s various websites were seized by the FBI and the U.K.’s National Crime Agency (NCA), which replaced the ransomware group’s homepage with a seizure notice and used the existing design of LockBit’s victim shaming blog to publish press releases about the law enforcement action.
The feds used the existing design on LockBit’s victim shaming website to feature press releases and free decryption tools.
Dubbed “Operation Cronos,” the effort involved the seizure of nearly three-dozen servers; the arrest of two alleged LockBit members; the release of a free LockBit decryption tool; and the freezing of more than 200 cryptocurrency accounts thought to be tied to the gang’s activities. The government says LockBit has claimed more than 2,000 victims worldwide and extorted over $120 million in payments.
In a lengthy, rambling letter published on Feb. 24 and addressed to the FBI, the ransomware group’s leader LockBitSupp announced that their victim shaming websites were once again operational on the dark web, with fresh countdown timers for Fulton County and a half-dozen other recent victims.
“The FBI decided to hack now for one reason only, because they didn’t want to leak information fultoncountyga.gov,” LockBitSupp wrote. “The stolen documents contain a lot of interesting things and Donald Trump’s court cases that could affect the upcoming US election.”
A screen shot released by LockBit showing various Fulton County file shares that were exposed.
LockBit has already released roughly two dozen files allegedly stolen from Fulton County government systems, although none of them involve Mr. Trump’s criminal trial. But the documents do appear to include court records that are sealed and shielded from public viewing.
George Chidi writes The Atlanta Objective, a Substack publication on crime in Georgia’s capital city. Chidi says the leaked data so far includes a sealed record related to a child abuse case, and a sealed motion in the murder trial of Juwuan Gaston demanding the state turn over confidential informant identities.
Chidi cites reports from a Fulton County employee who said the confidential material includes the identities of jurors serving on the trial of the rapper Jeffery “Young Thug” Williams, who is charged along with five other defendants in a racketeering and gang conspiracy.
“The screenshots suggest that hackers will be able to give any attorney defending a criminal case in the county a starting place to argue that evidence has been tainted or witnesses intimidated, and that the release of confidential information has compromised cases,” Chidi wrote. “Judge Ural Glanville has, I am told by staff, been working feverishly behind the scenes over the last two weeks to manage the unfolding disaster.”
LockBitSupp also denied assertions made by the U.K.’s NCA that LockBit did not delete stolen data as promised when victims agreed to pay a ransom. The accusation is an explosive one because nobody will pay a ransom if they don’t believe the ransomware group will hold up its end of the bargain.
The ransomware group leader also confirmed information first reported here last week, that federal investigators managed to hack LockBit by exploiting a known vulnerability in PHP, a scripting language that is widely used in Web development.
“Due to my personal negligence and irresponsibility I relaxed and did not update PHP in time,” LockBitSupp wrote. “As a result of which access was gained to the two main servers where this version of PHP was installed.”
LockBitSupp’s FBI letter said the group kept copies of its stolen victim data on servers that did not use PHP, and that consequently it was able to retain copies of files stolen from victims. The letter also listed links to multiple new instances of LockBit dark net websites, including the leak page listing Fulton County’s new countdown timer.
LockBit’s new data leak site promises to release stolen Fulton County data on March 2, 2024, unless paid a ransom demand.
“Even after the FBI hack, the stolen data will be published on the blog, there is no chance of destroying the stolen data without payment,” LockBitSupp wrote. “All FBI actions are aimed at destroying the reputation of my affiliate program, my demoralization, they want me to leave and quit my job, they want to scare me because they can not find and eliminate me, I can not be stopped, you can not even hope, as long as I am alive I will continue to do pentest with postpaid.”
In January 2024, LockBitSupp told XSS forum members he was disappointed the FBI hadn’t offered a reward for his doxing and/or arrest, and that in response he was placing a bounty on his own head — offering $10 million to anyone who could discover his real name.
After the NCA and FBI seized LockBit’s site, the group’s homepage was retrofitted with a blog entry titled, “Who is LockBitSupp? The $10M question.” The teaser made use of LockBit’s own countdown timer, and suggested the real identity of LockBitSupp would soon be revealed.
However, after the countdown timer expired the page was replaced with a taunting message from the feds, but it included no new information about LockBitSupp’s identity.
On Feb. 21, the U.S. Department of State announced rewards totaling up to $15 million for information leading to the arrest and/or conviction of anyone participating in LockBit ransomware attacks. The State Department said $10 million of that is for information on LockBit’s leaders, and up to $5 million is offered for information on affiliates.
In an interview with the malware-focused Twitter/X account Vx-Underground, LockBit staff asserted that authorities had arrested a couple of small-time players in their operation, and that investigators still do not know the real-life identities of the core LockBit members, or that of their leader.
“They assert the FBI / NCA UK / EUROPOL do not know their information,” Vx-Underground wrote. “They state they are willing to double the bounty of $10,000,000. They state they will place a $20,000,000 bounty of their own head if anyone can dox them.”
In the weeks leading up to the FBI/NCA takedown, LockBitSupp became embroiled in a number of high-profile personal and business disputes on the Russian cybercrime forums.
Earlier this year, someone used LockBit ransomware to infect the networks of AN-Security, a venerated 30-year-old security and technology company based in St. Petersburg, Russia. This violated the golden rule for cybercriminals based in Russia and former soviet nations that make up the Commonwealth of Independent States, which is that attacking your own citizens in those countries is the surest way to get arrested and prosecuted by local authorities.
LockBitSupp later claimed the attacker had used a publicly leaked, older version of LockBit to compromise systems at AN-Security, and said the attack was an attempt to smear their reputation by a rival ransomware group known as “Clop.” But the incident no doubt prompted closer inspection of LockBitSupp’s activities by Russian authorities.
Then in early February, the administrator of the Russian-language cybercrime forum XSS said LockBitSupp had threatened to have him killed after the ransomware group leader was banned by the community. LockBitSupp was excommunicated from XSS after he refused to pay an arbitration amount ordered by the forum administrator. That dispute related to a complaint from another forum member who said LockBitSupp recently stiffed him on his promised share of an unusually large ransomware payout.
A posted by the XSS administrator saying LockBitSupp wanted him dead.
KrebsOnSecurity sought comment from LockBitSupp at the ToX instant messenger ID listed in his letter to the FBI. LockBitSupp declined to elaborate on the unreleased documents from Fulton County, saying the files will be available for everyone to see in a few days.
LockBitSupp said his team was still negotiating with Fulton County when the FBI seized their servers, which is why the county has been granted a time extension. He also denied threatening to kill the XSS administrator.
“I have not threatened to kill the XSS administrator, he is blatantly lying, this is to cause self-pity and damage my reputation,” LockBitSupp told KrebsOnSecurity. “It is not necessary to kill him to punish him, there are more humane methods and he knows what they are.”
Asked why he was so certain the FBI doesn’t know his real-life identity, LockBitSupp was more precise.
“I’m not sure the FBI doesn’t know who I am,” he said. “I just believe they will never find me.”
It seems unlikely that the FBI’s seizure of LockBit’s infrastructure was somehow an effort to stave off the disclosure of Fulton County’s data, as LockBitSupp maintains. For one thing, Europol said the takedown was the result of a months-long infiltration of the ransomware group.
Also, in reporting on the attack’s disruption to the office of Fulton County District Attorney Fani Willis on Feb. 14, CNN reported that by then the intrusion by LockBit had persisted for nearly two and a half weeks.
Finally, if the NCA and FBI really believed that LockBit never deleted victim data, they had to assume LockBit would still have at least one copy of all their stolen data hidden somewhere safe.
Fulton County is still trying to recover systems and restore services affected by the ransomware attack. “Fulton County continues to make substantial progress in restoring its systems following the recent ransomware incident resulting in service outages,” reads the latest statement from the county on Feb. 22. “Since the start of this incident, our team has been working tirelessly to bring services back up.”
Update, Feb. 29, 3:22 p.m. ET: Just hours after this story ran, LockBit changed its countdown timer for Fulton County saying they had until the morning of Feb. 29 (today) to pay a ransonm demand. When the official deadline neared today, Fulton County’s listing was removed from LockBit’s victim shaming website. Asked about the removal of the listing, LockBit’s leader “LockBitSupp” told KrebsOnSecurity that Fulton County paid a ransom demand. County officials have scheduled a press conference on the ransomware attack at 4:15 p.m. ET today.
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