You may have noticed your friends, children or grandchildren obsessively playing a new mobile phone game called Flappy Bird - it had topped the Apple app charts and been downloaded 50 million times on Android before its creator Nguyen Ha Dong pulled the app.
But it appears as though the app has attracted the attention of criminals too, as the Trend Micro anti-scam blog has warned that a number of fake Flappy Birds apps are now available for download.
Security expert Graham Cluley explains: "The apps, which have been particularly rampant in unofficial Android app marketplaces in Russia and Vietnam, attempt to send SMS messages to premium rate services and then hide the responses from the phone's owners. In this way, the fraudsters earn money without the game player realising."
They are able to do this because when you download the fake app, you are asked to give the creators a number of "permissions", including the ability for them to send and receive SMS messages from your phone.
Trend Micro itself says Android users should be extra careful when installing apps, as cyber criminals have been known to cash-in using other popular app games such as Candy Crush, Angry Birds Space, Temple Run 2 and Bad Piggies.
Cluley adds: "See how many reviews an app has received – and check them out before downloading it to your Android phone. If it's a popular app like Candy Crush Saga or Instagram or Angry Birds, you would expect there to be plenty of reviews. If it doesn't have any reviews, but is a well-known app, there's a chance that you're looking at a fake version which might have sinister intentions."
"And, regardless of where you source your Android apps from, always check the permissions that your app requests. You should ask yourself, would a simple game really require need to send (potentially expensive) SMS messages?"