A new Android trojan has cropped up that records phone calls and related information, according to a blog post by an employee of security company Total Defense. The trojan is triggered when the Android device places or receives a phone call. It saves the audio file and related information to the phone's microSD card, and includes a configuration file with information on a remote server and settings used by the trojan.
According to the post, the trojan presents itself as an "Android System Message" that requires users to press an "Install" button for it to insert itself in the phone. Once installed, the trojan records all incoming and outgoing calls to a directory on the microSD card as .amr files, as well as information about the call, including its duration, in a text file.
One of the background services of the trojan can "send the recorded call files to the [remote] server when a fresh call record is created," Dinesh Venkatesan, author of the blog post, told Ars. However, due to a typo in the code, that portion of the process can't be carried out at present.
To be fair, the pop-up install dialog for the Trojan effectively describes in bullet points all the nefarious things it's about to do, including "record audio" and "read phone state and identity." Anyone paying a little attention to what their phone is doing would notice, but if the dialog is placed interstitially during another download that appears more legitimate and has visually similar install screens, it could rely on users' impatience to embed itself in the phone.
Venkatesan told Ars that the trojan has not been spotted in the wild, but rather on a "malware collection channel," and he wasn't sure how it would manifest itself in the real world. One of the most popular vectors for trojans and malware so far has been the Android Market store. While Google's remote kill switch can clean malware-ridden apps obtained from the store off infected handsets, as in the case of DroidDream Light, the damage from a trojan working with a remote server like this might so not easily be undone.