Check Point researchers discovered another widespread malware campaign on Google Play, Google’s official app store. The malware, dubbed “Judy”, is an auto-clicking adware which was found on 41 apps developed by a Korean company. The malware uses infected devices to generate large amounts of fraudulent clicks on advertisements, generating revenues for the perpetrators behind it. The malicious apps reached an astonishing spread between 4.5 million and 18.5 million downloads.

http://blog.checkpoint.com/2017/05/25/judy-malware-possibly-largest-malware-campaign-found-google-play/