Trojans that run on the Android operating system are usually either specially-crafted programs that are designed to look like desirable software (e.g., games, system updates or utilities), or copies of legitimate programs that have been repackaged or trojanized to include harmful components.
Trojans rely on tricking the user into believing that the program is authentic, so that they unwittingly install the program themselves. Trojans on the Android platform are often distributed using the same (or very similar) names and designs as popular programs found in online app marketplaces, to increase the chances that users will mistake the trojan for the legitimate app and install it instead.
Once the trojan is installed on the device, it silently performs its actual, unauthorized functions, which may range from harvesting personal data from the device, to sending premium SMS messages or intercepting SMS messages, connecting the device to a botnet and so on.
Examples of trojans on the Android platform include:
For more information about malware on the Android platform, see the latest Mobile Threat Reports.