The fake Android Defender — there's a real, less dubious Android Defender app found in the Google Play store — tricks users into paying for a fake "cleanup" service that will allegedly clear their devices of Trojans and viruses.

The experts at Sophos' Naked Security blog analyzed the fraudulent anti-virus software thoroughly. The app first warns users that their devices are "at risk of being infected," then prompts them to allow free scans of the devices.