Flappy Bird is making massive headlines this week after its creator took the game down because it was so addictive. Gamers started looking for the popular app elsewhere and some got more than they bargained for: malware.

Cybercriminals are taking advantage of Flappy Bird flying away and are pushing out clones that contain malicious software. It’s reportedly hard to tell the difference between the real game and the fake. But the phony apps are sending expensive text messages using a victim’s phone number.

“All of the fake versions we’ve seen so far are premium service abusers -- apps that send messages to premium numbers, thus causing unwanted charges to victims’ phone billing statements,” Veo Zhang, a mobile Relevant Products/Services threats analyst at Trend Micro, wrote in a blog post. “The fake Flappy Bird app asks for the additional read/send text messages permissions during installation -- one that is not required in the original version.”

How it Works

While the user is busy playing the game, this malware stealthily connects to a C&C [command & control] server Relevant Products/Services through Google Cloud Messaging to receive instructions, Zhang reports. Trend Micro’s analysis of the malware revealed that through this routine, the malware sends text messages and hides the notifications of received text messages with certain content.

“Apart from premium service abuse, the app also poses a risk of information leakage for the user since it sends out the phone number, carrier, Gmail address registered in the device,” Zhang said. “Other fake versions we’ve seen have a payment feature added into the originally free app. These fake versions display a pop up asking the user to pay for the game. If the user refuses to play, the app will close.”

A Viral Marketing Boost

Paul Ducklin, a security Relevant Products/Services researcher at Sophos, said allowing "off-market" app installs is a non-default option, and it produces a fairly stern warning from Google if you try to activate it. Ducklin said that the original Flappy Bird was free, with no trial period or fee, and the author made his money through ads presented by the game, not by selling the app.

“But, like writers, musicians and artists whose popularity surges when they die, Flappy Bird enjoyed a bigger-than-ever viral marketing boost upon its demise,” he wrote in a blog post. “So it's possible, even likely, that otherwise conservative users have been turning on the ‘unknown sources' feature so they can take a belated look at what the Flappy Bird fuss is all about.”

Using Common Sense

We caught up with Graham Cluley, an independent security analyst in London, to get his take on the latest Flappy Bird news. He told us it’s always better to buy Android apps directly from the official Google Play store -- and this is a good example of why.

“Although there have been cases of malware and shady apps getting into the official store, generally it's a lot safer to download Android apps from there than elsewhere. Wherever you source your Android apps from, always check the permissions that your app requests,” he said.

“You should ask yourself, would a simple game really need to send -- potentially expensive -- SMS messages? A little common sense can go a long way,” he added.