Android Package Files
The Trojan generally arrives within a repackaged .apk file from a legitimate application. The package name, publisher, and other details will vary and may be taken directly from the original application.
The following example has been seen used in the wild:APK:
Top Battery Application Name:
Battery Improve Version:
Since this threat comes bundled with a legitimate application, similar application details may be found in a legitimate version in the Android Marketplace. A repackaged, malicious version of the application can only be found on unofficial marketplaces.Permissions
When installing the Trojan, it will ask for one or more of the following permissions:
- Send SMS messages
- Determine your location through GPS and Internet-based methods.
- Read SMS or MMS messages
- Allow full Internet access
- Allow Bluetooth access
- Read contact data
- Read phone state and identity
- Retrieve a list of running applications
- Change the WiFi state.
Once installed an icon for the original application will appear. For example:Note:
This icon may also belong to a legitimate application on the Android Marketplace. Malicious versions of the application can only be found on unofficial marketplaces.Revenue generation
The Trojan then sends SMS messages to premium-rate numbers.
The phone numbers that the threat sends these messages to are either hard-coded into the threat, or downloaded in a configuration file from a predetermined website.Further actions
These types of Trojans usually contain further functionality besides sending SMS messages. Some of these actions include the following:
- Gather the IMEI number, phone number, phone name, carrier, and Android version and send it to a remote location.
- Send a list of installed and running packages to a remote host.
- Modify WiFi and network settings.
- Replace the advertisement networks used in some applications with one of the attacker's choosing, and not associated with the developer of the genuine application.
Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":