While macOS is a very secure operating system, malware can get through, especially if users are opening unsafe or unknown files. One such vulnerability was recently discovered that could allow an attacker to control a Mac running any macOS version up to Big Sur simply by clicking on an email attachment.
Researcher Park Minchan (via Bleeping Computer) found that files that have the inetloc extension can be used to exploit a vulnerability in the macOS Finder. In a blog post on SSD Secure Disclosure, Minchan reports that inetoc files “can be embedded inside emails which if the user clicks on them will execute the commands embedded inside them without providing a prompt or warning to the user.” As SSD Secure Disclosure explains, if the inetloc file is attached to an email, opening the attachment “will trigger the vulnerability without warning.”
Read more at Macworld.com