It simply goes to show that users should never download software from a third-party website or marketplace.
The cybersecurity researchers at Jamf discovered that cybercriminals are trojanizing legitimate Mac software apps with malware and uploading them to The Pirate Bay and other pirated software sites, where users download them and unknowingly infect their devices. The attackers use XMRig cryptojacking malware to execute the XMRig utility.
For your information, XMRig is a command-line cryptominer. It isn’t new on Mac, as Trend Micro analyzed a sample in February 2020. This tool is used for legitimate purposes, but its open-source, adaptable design has made it a popular choice among threat actors.
The newly discovered XMRig implementation was disguised as Final Cut Pro, Apple’s video editing software. Attackers used the Invisible Internet Project (I2P) in both iterations of XMRig for outbound communication, raising confusion about whether the infections were connected or part of something larger.
The malicious version of Final Cut Pro is unauthorized by Apple. It executes XMRig in the background. When it wasn’t initially dubbed as malicious by any security mechanism on VirusTotal, from Jan 2023 onwards multiple vendors detected the malware. Still, most of the malicious apps remain undetected.
Researchers from Jamf searched for the malware source on The Pirate Bay and found one with a matching hash to the trojanized version and a series of Apple Mac apps, including Logic Pro and Photoshop.
It is worth noting that all apps were uploaded to The Pirate Bay by the user called “wtfisthat34698409672.” Moreover, they found numerous versions of Final Cut Pro.
In a blog post, researchers said that,
“We suspected that the Mach-O sample arrived packaged in a DMG (an Apple image format used to compress installers) for Adobe Photoshop CC 2019 v20.0.6. However, the parent file was not successfully sourced.”Jamf
Further probing revealed three generations of malware—the first generation started in August 2019 and was a standard malware implementation. The second generation started in April 2021 and wasn’t detected by VirusTotal until February 13, 2023. This version was different as there were additional hidden files, but no persistence mechanism was noted.
Instead, the malware opened with the app and stopped functioning when the app was closed. The third generation had greater stealth features, as there weren’t any hidden executables, but only one large binary with base64-encoded components and LZMA compression.
New versions of these malicious Mac apps started appearing on The Pirate Bay within just 24 hours of Apple’s app update releases and were disguised as legitimate processes.
Researchers state that this isn’t a typical malware campaign and is more like a methodology for delivering malware. Still, users should beware of trojanized apps and avoid downloading software from unknown sources.