Google has identified and disabled 192 Chrome browser extensions that injected rogue ads into Web pages opened by users without being upfront about it. The company will scan for similar policy violations in future.
The action followed a study that the company conducted together with researchers from University of California Berkeley and which found that more than five percent of Web users who accessed Google websites had an “ad injector” installed.
The deceptive Chrome extensions were detected as part of that study, but the researchers also found ad injectors affecting browsers such as Internet Explorer and Mozilla Firefox, on both Windows and Mac OS X.
Google doesn’t specifically ban extensions published on the Chrome Web Store from injecting ads into Web traffic, as long as they clearly inform users about what they do, but the study found that around a third of extensions with such functionality were actually malware.
The larger problem is that rogue ad injection, which is used for advertising fraud, is not done only through browser extensions. There are software applications that can do this at the network layer, outside of the browser, or by hooking the browser process without installing an extension.