Researchers from the security firm Trend Micro announced the discovery of a number of applications that use smartphones and tablets to mine cryptocurrency. These apps acquire Monero by using the Coinhive Javascript cryptominer, a code that was originally designed to allow websites to mine cryptocurrency from its visitors in exchange for an ad-free experience. Among the apps that contain the cryptominers are the Recitiamo Santo Rosario Free, an application that supposedly helps people who read the rosary, and the Safetynet Wireless app, which claims to provide cash, discounts, and free data. The two applications have both been removed from the Google Play Store, although before it was taken down, it seems that each app was downloaded on more than 10,000 handsets. After these apps are installed, it will load the Coinhive code and cryptomining will then begin using the attacker’s site key. Users have no idea that mining is already taking place since the entire procedure happens in a webview that is set in invisible mode. The system also fails to detect these apps due to the use of native code injection, a method that bypasses security restrictions.
The researchers also discovered that cybercriminals often take legitimate versions of an app, add codes needed to mine cryptocurrencies, and upload the modified software again to the Google Play Store. For example, an app dubbed as the Car Wallpaper HD contains modified cpuminer codes that can mine a variety of cryptocurrencies including Magicoin, Feathercoin, and Vericoin. This app was installed in less than 500 devices, but the developer was able to mine coins with a total value of around $170, despite the small number of downloads.
The researchers from Trend Micro noted that there are doubts about the ability of mobile devices to mine cryptocurrencies. However, Samsung was able to mine Bitcoin using 40 units of the Samsung Galaxy S5, with the manufacturer claiming that eight units of the Galaxy S5 are better at mining Bitcoin than a personal computer equipped with an Intel Core i7 2600 processor. Unfortunately, installing apps with cryptominers can severely impact the performance of the device since the CPU usage will always be exceptionally high, which, in turn, also results in reduced battery life. Trend Micro is advising users to always observe if there is any performance degradation once an app is installed on a device.
