Armed with an impressive-looking shield logo, security app Virus Shield shot to the top of the sales charts on Android last week, becoming the top new paid download on Google Play, according to Appbrain’s statistics - and offering "protection for personal information".

There was one, tiny, problem: the app was a fake. Virus Shield wasn’t a Trojan or spyware - both of which are common on Google’s unpoliced app store, as reported by We Live Security here, it just didn’t do anything.

The app was downloaded more than 10,000 times, at a price of $4, according to Android Police, and users rated it an impressive 4.7 out of 5. Neowin described the app as "a complete scam".

Recruiting experts via Google Plus, Android Police analyzed the code of Virus Shield, and found that its only function was that the logo changed slightly when tapped on the touchscreen. The code contained no other security features whatsoever.

The reviews were presumably fake - but the high score was enough to tempt a sufficient number of buyers to gain the app some explosure on the store, according to Gizmodo. ESET’s guide to spotting scammy apps details some of the tricks used to sell malicious - or useless - apps. Popular game FTL appeared on Play, but buyers were forced to give it a five-star rating to start playing. It didn’t work, of course.

Virus Shield promised that it “Prevents harmful apps from being installed on your device” and “protects your personal information.”

The app was pulled from the store by Google, but a search for its name reveals a huge number of ‘antivirus’ apps from unknown developers, offering vague promises of protection for phones.

ESET's guide to how to spot - and avoid - such apps details telltale signs that an app isn't what it seems. Like many 'fakes', Virus Shield was by an unknown developer, whose descriptions on other sites were less than flattering.

Android Police wrote, “Let's not mince words here. This is fraud, pure and simple, and the developer "Deviant Solutions" potentially made considerable amounts of money based on a complete lie. We assume that a lot of the initial reviews were fake, but now that it's on the top of the charts, at least a few people will be buying it in the belief that it will protect them.”

ESET’s in-depth guide to spotting ‘bad’ apps on Google Play can be found here.