The Sneaky Simple Malware That Hits Millions of Macs

The popular misconception that Macs don’t get viruses has become a lot less popular in recent years, as Apple devices have weathered their fair share of bugs. But it’s still surprising that the most prolific malware on macOS—by one count, affecting one in 10 devices—is so relatively crude.

This week, antivirus company Kaspersky detailed the 10 most common threats its macOS users encountered in 2019. At the top of the list: the Shlayer Trojan, which hit 10 percent of all of the Macs Kaspersky monitors, and accounted for nearly a third of detections overall. It’s led the pack since it first arrived in February 2018.

You’d think that such prevalence could only be achieved by comparable sophistication. Not so! “From a technical viewpoint Shlayer is a rather ordinary piece of malware,” Kaspersky wrote in its analysis. In fact, it relies on some of the oldest tricks in the books: convincing people to click on a bad link, then pushing a fake Adobe Flash update. Even the trojan’s payload turns out to be ho-hum: garden variety adware.