If Steve Jobs is buried in a grave, he’s probably spinning faster than a hard drive. For the past few weeks, my Mac has been running Microsoft Defender – security software for an operating system that Jobs famously claimed didn’t get viruses, made by the company he constantly accused of shoddy security.
Is Microsoft Defender a prank, a marketing stunt being played by Microsoft’s PR department? Or is it actually useful protection for Mac owners? I’ve been testing it for a few weeks to find out.
The back story
Fifteen years ago, the very idea of Microsoft making security software for the Mac would have been unthinkable.
At the time, Microsoft Windows was the butt of Apple’s advertising jokes. The very first of the infamous “I’m a Mac, I’m a PC” ads featured a sneezing PC guy moaning about catching a nasty virus, stood next to the immune, irritatingly smug Mac.
Even at the time, the advertising claim was dubious. Yes, the number of Windows viruses circulating far outnumbered those targeting the Mac. They still do, although Mac threats have increased alongside the growing popularity of Macs. The Mac isn’t immune from attack – it never has been.
Microsoft releasing Mac security software in the mid-2000s would also have been unthinkable because it just didn’t do security software at the time. Microsoft Security Essentials, its first foray into Windows client security software, wasn’t released until 2009 and it wasn’t very good. It was widely panned for failing to detect malware as well as third-party products.
Much has changed over the past decade or so. In the comparative tests of Windows security suites published by independent labs such as AV-Test, Microsoft Defender (as Security Essentials is now called) does as well as the paid-for security suites. Given it’s bundled free with Windows 10 and 11, it’s driven a tank through the Windows anti-virus market. It’s why security suites such as Norton are resorting to increasingly desperate tactics, such as bundling crypto miners into their software in order to boost revenue.
Microsoft Defender for Mac
So now Microsoft Defender has landed on the Mac. It’s part of the company’s all-encompassing Microsoft 365 package, which includes the Office products and now Defender for PC, Mac, Android and even iOS.
Microsoft is positioning Defender as a security dashboard for all of your devices. Parents, for example, can open the Defender app on their phone and get a reassuring reminder that all of the family’s other computing devices are protected. It’s not a marketing prank, although you suspect there was a degree of sniggering in the Microsoft press office when this was released…
Does Microsoft Defender do its job? Well, it’s not the most proactive of security suites. There’s no active email scanning, for example, and I get plenty of malicious emails: fake delivery scams, offers from Saudi princes, spoof Amazon emails. Defender doesn’t throw itself in front of the truck, begging you not to open or reply to the mail. But if you clicked on an attachment that was trying to install something nasty, Defender promises to get in the way. If macOS’s own security tools don’t intervene first.
I ran a full scan on my MacBook Pro yesterday, and after 20 minutes of probing it found two Trojans (both in my email app) and offered to put them both in quarantine. Oddly, you have to enter your macOS password to find out exactly what the malware is, but I think that’s a macOS restriction more than a Microsoft one.
Defender is pretty lightweight, too. It sits in the background and doesn’t consume significant resources. I’ve just checked the Mac Activity Monitor and it’s halfway down the list, nibbling on 60MB of RAM. For comparison, top-of-the-list Dropbox is using 447MB. Even when it was doing a full scan, it failed to break into the top five memory users.
So, if you’re a Microsoft 365 subscriber and you want something to keep an eye on your Mac, you could do worse than Microsoft Defender. No joke.