While installing ad blocking extensions is becoming the norm for everyday web surfers, the number of imposter and malicious browser extensions has increased alongside it, taking advantage of the less savvy users.

AdGuard, a company that provides its own paid ad blocking service, has released a report listing five fake extensions that have made their way to top spots in Chrome’s Web Store and been installed by millions of users.

Popularity contest

These malicious extensions spam keywords and code to cheaply climb the ranks in search results for phrases such as 'adblocker' and 'ad block' and, considering their relatively similar names and appearance to legitimate extensions, end up getting downloaded by users.

AdGuard reports that more than 20 million users in total have downloaded and installed the five extensions, with one in particular topping out at 10 million downloads.

The fake extensions appear to do what it says on the tin as they use copied code from legitimate blockers, cloning their functionality entirely. The catch, however, is that they add their own malicious code to gain access to users’ browsers and information.

The five extensions mentioned in the AdGuard report have since been taken down by Google. While two of them aren’t strictly ad blockers, they abuse the same exploit. Here’s the list:

AdRemover for Google Chrome™



uBlock Plus



Adblock Pro



HD for YouTube™



Webutation

If you plan on using an ad blocker, it's well worth doing a bit of background research on browser extensions before installing them to be sure they have known authors and are recommended by reputable sources.