However, says Wardle: “The fact that known malware got notarized in the first place raises many questions.”Īnd worryingly, Wardle later found the campaign is back up and running-on August 30 the adware campaign was still live and serving up new payloads.

Wardle reported his findings to Apple, which quickly revoked the certificates, rescinding their notarization status so malicious payloads will now no longer run on macOS. Taking this into account, he warns users against trusting all notarized Apple software. “As such, it not too surprising that this insidious malware has continued to evolve to trivially side-step Apple’s best efforts,” Wardle concedes.

OSX.Shlayer could be the most prevalent malware infecting macOS systems, Kaspersky says-and the ultimate goal of OSX.Shlayer is to download and persistently install macOS adware.Īdding to this, OSX.Shlayer is clever, and has quickly evolved, finding ways to bypass macOS security mechanisms. The notarized payloads appear to be the OSX.Shlayer malware, Wardle discovered. MORE FROM FORBES Apple Reveals Touch ID And Face ID Are Coming To Safari By Kate O'Flaherty OSX.Shlayer malware In addition, these malicious payloads are allowed to run-even on macOS Big Sur. That means the malicious payloads were submitted to Apple, prior to distribution: Apple scanned and apparently detecting no malice, inadvertently notarized them. However, the campaign originating from homebrew.sh leveraged adware payloads that were fully notarized. These types of campaigns usually use un-notarized code, so are stopped in their tracks. If a user inadvertently visited homebrew.sh, after various redirects an update for “Adobe Flash Player” would be aggressively recommended.

On August 28, Twitter user Peter Dantini noticed that the website homebrew.sh (not to be confused with the legitimate Homebrew website brew.sh), was hosting an active adware campaign. Wardle cites the example of Homebrew, hosted at brew.sh. “If software has not been notarized, it will be blocked by macOS, with no option to run it via the alert prompt,” Wardle explains, adding: “With the goal of stymieing the influx of malicious code targeting macOS, notarization seemed like a promising idea. Sadly, not all promises are kept.” This ensures that Apple can inspect and approve all software before it is allowed to run on new versions of macOS. Apple introduced notarization requirements in macOS 10.15 (Catalina), requiring developers to submit their applications to Apple before distribution to macOS users.

Apple virus scan alert