Mac Adware Infections Increased by 400% in 2019

Malwarebytes, one of the largest providers of anti-malware software around, released its “State of Malware Report” on Tuesday, offering some insight into how malware and adware threats have evolved over the last 12 months. Most eye-catching among the report’s findings is the fact that it detected 400 percent more adware affecting Macs than it did in 2018, though it does offer the caveat that this is partially due to a growing number of Mac users running its software.

The report doesn't say exactly how many people actually have Malwarebytes software installed on their computers, but it does provide a “threats per endpoint” metric that attempts to make an apples-to-apples comparison between the 2018 and 2019 figures. The idea here is that you’re getting a per capita figure, as each “endpoint” represents a single user device, and even after adjusting for the increased user count, the numbers still look grim: Malwarebytes detected an average of 11 threats (ie. distinct instances of adware) per endpoint in 2019, a steep rise from 2018’s figure of 4.8 threats per endpoint.

While these figures paint a fairly bleak picture for Mac users, there are multiple factors worth considering before beginning to panic. For one, the vast majority of this increase in threats has been from adware, which is relatively benign compared to more serious malware threats like trojans, ransomware, and stalkerware. Adware is generally the least serious threat in the hierarchy of unwanted software, and the Mac figures for the more serious threat categories saw a much smaller rise.

It’s also worth keeping in mind that a greater diversity of threats detected on the average endpoint doesn’t necessarily mean that a greater number of endpoints are being infected—it could simply mean that adware is coming in a wider array of flavours these days, and the people getting infected are inviting in that increased diversity of flavours. That said, the increase in threats-per-endpoint combined with the fact that Malwarebytes saw a big uptick in the number of Mac users installing its software does point to an increased prevalence of Mac adware—many users only install anti-malware software when they suspect they may have been infected, after all.

So while one can quibble about the severity of the Mac adware epidemic, all evidence points to a threat environment that’s increasingly hostile to Mac users, and for good reason. As much as Apple has always loved to brag about how much better its security is than its competitors’, its historically smaller user base compared to Windows simply made it a less desirable target for malware makers. Now that it's made gains in the market, however, it’s inevitable that more effort will be put into threats targeting its operating system.