The Mac Malware of 2021

But I actually don't run it all that often. Instead, I try to monitor activity, like network access, or writes to file system areas that might indicate weird behavior.

But -- Now that my kid is heavy into macOS usage, and relatively inexperienced regarding possible malware vectors, I can't rely on runtime observation. I've installed a DNS block list for malware sites, log our net traffic, and periodically scan with clamAV.

For my own box, I try to keep things simple and learn how the system normally behaves, in the hope that I might notice if something weird is going on. I realize this is not an adequate solution.

I use Little Snitch for real-time monitoring of network activity; it can get distracting but it's a good way to see how much a process or application likes to phone home.

https://www.obdev.at/products/littlesnitch/index.html

It's worth looking at some of the tools provided by the author of the OP, ObjectiveSee.

https://objective-see.com/products.html

I used BlockBlock for a while. It pops up an alert when software tries to install itself into places that might run without your knowledge. LaunchAgents and system extensions. I don't recall ever seeing actual malware with this tool.

The author runs a Mac Security conference that seems to generate good work among the attendees, those who track Mac security best practices. Sysadmins and researchers. I have not attended, so my endorsement is perhaps not useful... Back in the 20th Century, I built and ran a business Mac network with hundreds of nodes, which was considered pretty big at the time. Focused conferences and workshops were amazing in getting an idea on how much I needed to learn.

[1] https://objective-see.com/products/lulu.html