Two malicious apps were removed by google which had over 1.5 million downloads after being found that they serve adware. The apps, "Sun Pro Beauty Camera and Funny Sweet Beauty Selfie Camera — were also found to have “more advanced functionality than your average adware,”
They required users to allow access to functions more than it needed which let them use mic or record audio without users knowledge. And even show full screen ads without even opening them.
We would like to warn you about the permissions you give to apps you install, read the permission before you give it access and think why would this app need this permission. For example, why would a photography app need recording permission or location permission?
Credit : thenextweb.com