According to reports, 25 million Android devices around the world have been infected by a virus called Agent Smith, of which 15 million are in India. The Agent Smith virus pops ads on infected phones, and is reportedly infecting devices via third party app stores. Once the virus has made its way onto your device, it conceals itself by renaming itself to something like Google Updater, which most users would skim over without a second thought.
Check Point further reported that the virus is spreading via third party app stores.
In order to avoid being infected, avoid downloading and installing apps from third party app stores and keep your downloads limited to only the Play Store. Be sure to go over permissions that you give to installed apps. Especially apps with Google in their name as that’s what the app disguises itself as.