The 'free' version of the Android app appears to be an infected piece of code that, while it functions like the paid-for edition, generates text messages to everyone in the user's directory telling them that the user is downloading files illegally from unauthorized sites.
According to Irfan Asrar, a security researcher with Symantec's Tokyo operation, when the free version of the Andorid app is run, "the user is presented with a dialog box that gives the appearance that the app is in the process of being compromised or cracked, when in fact, the app is gathering and attempting to send back sensitive data (name, phone number, IMEI information, etc.) to an external server."
Additionally, he says, the Android app sends out the offending text message to all the user's contacts.
The Symantec researcher goes on to say that the trojan within the cracked version of the Android app concludes with a signoff message to the user, "reminding them to check their phone bill, as well as providing an option of buying the legitimate version of the app from the Android App market."
"Although this isn't the first case of disciplinary justice being used as means to send a message against piracy, this is the first of its kind discovered on the mobile landscape", he notes in his security blog.