We’re going to let you in on a little cybersecurity secret… There’s malware on Mac computers. There pretty much always has been.

As revealed in our 2024 ThreatDown State of Malware report, a full 11% of all detections recorded by Malwarebytes on Mac computers in 2023 were for different variants of malware—the catch-all term that cybersecurity researchers use to refer to ransomware, trojans, info stealers, worms, viruses, and more.

That 11% figure may not sound imposing but remember that many people today still believe that Apple devices, including Mac computers, are invulnerable to cyberinfections because of some sort of vague “Apple magic.”

In reality, “Apple magic” is more a byproduct of old advertising (this 2006 commercial from the “I’m a Mac, and I’m a PC” series did irreparable harm) and faulty conclusions concerning cybersecurity’s biggest breaches and attacks: People mistakenly believe that because most attacks target Windows computers and servers, no attacks target Macs.

The truth is far more nuanced, as the visible, overwhelming focus of cyberattacks on Windows machines is a consequence of Microsoft’s long-standing success in business computing.

For decades, every multinational corporation, every local travel agency, every dentist, every hospital, every school, government, and city hall practically ran on Windows. This mass adoption was good for Microsoft and its revenue, but it also drew and maintained the interests of cybercriminals, who would develop malware that could impact the highest number of victims. This is why the biggest attacks, even today, predominantly target Windows-based malware and the sometimes-unpatched vulnerabilities found in Windows software and applications.  

Essentially, as Windows is the biggest target, cybercriminals zero in their efforts respectively.

But new information last year revealed that could all be changing.

Mac malware tactics shifted in 2023

Apple’s desktop and laptop operating system, macOS, represents a 31% share of US desktop operating systems, and roughly 25% of all businesses reportedly utilize Mac devices somewhere in their networks.

Already, the cybercriminals have taken note.

In April 2023, the most successful and dangerous ransomware in the world—LockBit—was found to have a variant developed for Mac. Used in at least 1,018 known attacks last year, LockBit ransomware, and the operators behind it, destroyed countless businesses, ruined many organizations, and, according to the US Department of Justice, brought in more than $120 million before being disrupted by a coordinated law enforcement effort in February of this year.

While the LockBit variant for Mac was not operational upon discovery, the LockBit ransomware gang said at the time that it was “actively being developed.” Fortunately, LockBit suffered enormous blows this year, and the ransomware gang is probably less concerned with Mac malware development and more concerned with “avoiding prison.”

Separately, in September 2023, Malwarebytes discovered a cybercriminal campaign that tricked Mac users into accidentally installing a type of malware that can steal passwords, browser data, cookies, files, and cryptocurrency. The malware, called Atomic Stealer (or AMOS for short) was delivered through “malvertising,” a malware delivery tactic that abuses Google ads to send everyday users to malicious websites that—though they may appear legitimate—fool people into downloading malware.

In this campaign, when users searched on Google for the financial marketing trading app “TradingView,” they were sometimes shown a malicious search result that appeared entirely authentic: a website with TradingView branding was visible, and download buttons for Windows, Mac, and Linux were clearly listed.

But users who clicked the Mac download button instead received AMOS.

Just months later, AMOS again wriggled its way onto Mac computers, this time through a new delivery chain that has more typically targeted Windows users.

In November, Malwarebytes found AMOS being distributed through a malware delivery chain known as “ClearFake.” The ClearFake campaign tricks users into believing they’re downloading an approved web browser update. That has frequently meant a lot of malicious prompts mimicking Google Chrome’s branding and update language, but the more recent campaign imitated the default browser on Mac devices—Safari.

As Malwarebytes Labs wrote at the time:

“This may very well be the first time we see one of the main social engineering campaigns, previously reserved for Windows, branch out not only in terms of geolocation but also operating system.”

Replace “magic” with Malwarebytes

Cyberthreats on Mac aren’t non-existent, they’re just different. But different threats still need effective protection, which is where Malwarebytes Premium can help.

Malwarebytes Premium detects and blocks the most common infostealers that target Macs—including AMOS—along with annoying browser hijackers and adware threats such as Genieo, Vsearch, Crossrider, and more. Stay protected, proactively, with Malwarebytes Premium for Mac.

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We don’t just report on threats—we remove them

Cybersecurity risks should never spread beyond a headline. Keep threats off your devices by downloading Malwarebytes today.

Cybercriminals are targeting Mac users interested in cryptocurrency opportunities with fake calendar invites. During the attacks the criminals will send a link supposedly to add a meeting to the target’s calendar. In reality the link runs a script to install Mac malware on the target’s machine.

Cybersecurity expert Brian Krebs investigated and flagged the issue.

Scammers, impersonating cryptocurrency investors, are active on Telegram channels to get interested people to attend a meeting about a future partnership.

One of those investors called Signum Capital tweeted a warning on X in January that one of their team members was being impersonated on Telegram and sending out invites by direct message (DM).

Heads up! A fake account pretending to be one of our team members is going around DM-ing people on Telegram.

The screenshots below is from the scammer please take note and be alert. pic.twitter.com/6hFcUsaGtZ

— Signum Capital (@Signum_Capital) January 22, 2024

The criminals reach out to targets by DM on Telegram and ask if they have an interest in hearing more about the opportunity in a call or meeting. If they show interest they will be sent a fabricated invitation for a meeting. When the times comes to join the meeting the invitation link doesn’t work. The scammers tell the victim it’s a known issue, caused by a regional access restriction, which can be solved by running a script.

We asked Malwarebytes Director of Core Technology and resident Apple expert Thomas Reed to look at this method. This isn’t the first time criminals have used scripts to compromise users, he told us.

“AppleScript has been used against Mac users with moderate frequency by malware creators over the years. It has the advantage of being very easy to write, and if compiled, is also extremely difficult to reverse engineer.”

According to Reed, AppleScripts can be provided in a few different forms. One is a simple .scpt file that opens in Apple’s Script Editor app. This has a few drawbacks for criminals: A victim would need to click something within Script Editor to run the script, and they would able to see the code, which might be a problem because AppleScript tends to be more human readable than most other scripts. However, there are ways to obfuscate what the code is doing, and many users won’t bother to read it anyway.

Another option is an AppleScript applet. This is something that acts like a normal Mac app. It contains a basic AppleScript executable and the script to be run. In this form, the script can be code signed, notarized, given an icon, and otherwise made to appear more trustworthy. The code could be pretty bland, and unlikely to trigger any kind of detection from Apple’s notarization process, but could download and execute something less trustworthy.

Scripts have another advantage for criminals, Reed warned.

“AppleScripts also have the advantage of being able to very easily get administrator permissions.”

A script that attempts to run a command with administrator privileges will ask users to authenticate, triggering a password dialog.

If the user enters their password, the script doesn’t actually get to see it, but everything else the script attempts to do “with administrator privileges” will successfully run as root without further authentication. This makes it very easy for the script to show a standard authentication request dialog and trick the user into giving root permissions.

“So, in summary, AppleScript can be quite effective for writing malware. In fact, some malware has been written exclusively – or almost exclusively – in AppleScript, such as OSX.DubRobber or OSX.OSAMiner.”

In this case, the script was a simple Apple Script that downloaded and executed a macOS-oriented Trojan. The nature of the Trojan is unknown, but it certainly won’t surprise anyone if it turns out it was a banking Trojan that specializes in stealing cryptocurrencies.

Recognizing the scam

To avoid falling victim to these scammers, it’s good to know a few of their tactics.

• Targets are approached by DM on Telegram.
• Topics are cryptocurrency investment opportunities.
• The scammers have a preference for the Calendly scheduling platform.
• A fake “regional access restriction” creates a sense of last minute urgency.
• The script had the .scpt (Apple script) extension.
• The script was hosted on a domain that pretended to be a meeting support site.

The presence of Mac malware is unfortunately still underestimated, but you can find protection by Malwarebytes for Mac and protect Mac endpoints in your environment by ThreatDown solutions.

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We don’t just report on threats—we remove them

Cybersecurity risks should never spread beyond a headline. Keep threats off your devices by downloading Malwarebytes today.

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.”

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.

Update: Added comment from Calendly.