Shocking: Google says 5% of users have ad-injection malware

If your computer gets infected with malware despite you doing your best to avoid dubious sites, Google has revealed one reason.

In a startling disclosure, the search giant says that about five per cent of internet users visiting Google's sites and services have at least one ad-injecting malware installed on their browsers.

The study conducted in collaboration with researchers at the University of California, Berkeley, is based on an analysis of 100 million page views across Google's sites through virtually any browser, whether Chrome, Firefox or Internet Explorer. It classified about a third of these ad injectors as ''outright malware''.

It was further discovered that out of those 5 per cent of users that have at least one ad injector installed, one-third evidently had four of them running simultaneously and half were running two.

Google will publish this data to raise awareness about unwanted ad injectors as they encourage an unhealthy ecosystem for users, advertisers, and publishers, a TechCrunch report quoted Google Safe Browsing engineer Nav Jagpal as saying.

Recently, Lenovo was embroiled in a similar controversy. Its laptops were found to be pre-installed with Superfish, an ad injector that also put the system's encryption at risk (See: Lenovo hit with lawsuit over Superfish ''spyware'').