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Following the fake versions of Instagram, Angry Birds Space, and Farm Frenzy apps, we recently spotted a website offering different fake Skype mobile apps for Android. But based on our analysis, these apps are actually malware that run on older Symbian versions or Android devices installed with apps that enable execution of Java MIDlet. Once installed, the malware send messages to premium numbers without users’ consent.

The website http://{BLOCKED}ndroidl.ru offers different versions of Skype app for Android. The said site is hosted on Russian domains, similar to the webpages we’ve seen hosting the fake Instagram and Angry Birds Space apps. During analysis, we attempted to download the said app, but noticed that the said app was being downloaded from another website, http://{BLOCKED}mobile.ne.

We also tried downloading the other Skype mobile app versions being offered by the site. Doing so, however, only lead us to the same .JAR file (instead of an .APK file, the expected download file for Android apps) downloaded from the same malicious site. This .JAR file (detected by Trend Micro as JAVA_SMSSEND.AB) is a Java MIDlet that poses as an installer of Skype for the Android platform. Once executed, the file displays the following interface:

Should users press the left soft key of their smartphone, it displays the following:

However, pressing the right soft key redirects the mobile device’s browser to the URL http://{BLOCKED}1.net/?u=1l4zi3m938o80vl. This malicious app functions to send SMS messages to specific numbers. As a result, affected users incur unnecessary monetary charges for these messages.

Though these fake Skype apps are marketed specifically to Android users, this malicious .JAR file executes on pre-SIS (Software Installation Script) Symbian phones or certain versions of Android that run Java MIDlet. For Android devices to run Java MIDlet, users must first install an app that enables the device to execute the said file. Typically, these type of apps are available on third-party app stores.

To have an an overview of the latest threats targeting Android devices, you may refer to our infographic Behind the Android Menace: Malicious Apps.

Trend Micro protects users from this threat via Smart Protection NetworkT , which detects and deletes this malicious .JAR file. Access to related websites is also blocked via web reputation service. As an added precaution, users must refrain from downloading apps from dubious websites. Users should also make it a habit to read mobile apps ratings and reviews, to know which apps are safe to download.

To know more about how to enjoy your mobille devices safely and securely, you may refer to our comprehensive Digital Life e-guides below:

• When Android Apps Want More Than They Need
• 5 Simple Steps to Secure Your Android-Based Smartphones

With additional analysis from Christopher So.