  Online advertisers and analytics services (or trackers), are constantly
tracking users activities as they access web services either through browsers
or a mobile apps. Numerous tools such as browser plugins and specialized mobile
apps have been proposed to limit intrusive advertisements and prevent tracking
on desktop computing and mobile phones. For desktop computing, browser plugins
are heavily studied for their usability and efficiency issues, however, tools
that block ads and prevent trackers in mobile platforms, have received the
least or no attention.
  In this paper, we present a first look at 97 Android adblocking apps (or
adblockers), extracted from more than 1.5 million apps from Google Play, that
promise to block advertisements and analytics services. With our data
collection and analysis pipeline of the Android adblockers, we reveal the
presences of third-party tracking libraries and sensitive permissions for
critical resources on user mobile devices as well as have malware in the source
codes. We analyze users' reviews for the in-effectiveness of adblockers in
terms of not blocking ads and trackers. We found that a significant fraction of
adblockers are not fulfilling their advertised functionality.
