According to a study Google conducted with researchers at the University of California, Berkeley, 5 percent of people visiting Google’s sites and services now have at least one ad injector installed.
When it comes to malware, ad injectors may seem relatively benevolent at first. They put an ad on your Google Search page that didn’t belong there, for example. That’s annoying, but doesn’t seem dangerous. But ad injection was pretty much what Lenovo’s Superfish was doing and that created plenty of security issues for users. Indeed, the research, which is based on the analysis of 100 million pageviews across Google’s sites from Chrome, Firefox and Internet Explorer, classified about a third of these injectors as “outright malware.”