Mac users are urged to update their systems to Big Sur 11.3 as soon as possible in order to patch a vulnerability that allows a malware known as Shlayer to bypass all of Apple’s security measures, including Gatekeeper and File Quarantine. The problem stems from a logic error in Apple’s operating system that misclassifies Shlayer as a safe file. In truth, Shlayer is malicious and it burrows deep into the user’s system, from where it launches an adware scam.