Creating and distributing fake antivirus programs (also called scareware) is a lucrative business. The perpetrators use drive-by downloads or other sneaky techniques to get the fake antivirus onto your device, then display alarming warnings about made-up security threats.
Scanning for malware with the fake AV is free and super-fast since it’s not actually doing anything. But if you naively ask the fake AV to fix the problems it found, you’ll find it demands cash up front. Even worse are the ones that encrypt your entire device, rendering it useless unless you pay to have it unlocked.
Another method that hackers use to steal your money is to insert Trojans into the antivirus app code. Just recently Google removed from their store four fake antivirus apps loaded with banking trojan that can intercept information for malicious attacks.
Some of these malicious trojan have an automatic transfer system or ATS, This unique system allows attackers to automatically transfer funds from the victim’s account without any human intervention.
To keep yourself safe from potentially harmful apps, never blindly trust any programs from the Google Play Store, especially if they offer you so-called free services, and restrict the number of installed apps on your device to a bare minimum.