MMSnap: An MMS based forensic system for recovering stolen phones

Mobile phone theft has been a growing problem of modern society, but it is difficult to recover lost phones because owners often have no clue to culprits. To address the problem, we propose MMSnap, a new forensic system based on Multimedia Messaging Service (MMS) for recovering stolen phones. When a user finds his phone has been stolen, he simply calls the phone using a predefined number saved in our system. No matter the culprit answers the call or not, once the system detects the number it secretly takes silent snapshots when he hangs up the phone. Even if the culprit replaces the SIM card, our system can still be triggered when he answers or makes a phone call, because it checks the state of the SIM card when processing each incoming or outgoing call. We leverage MMS to send snapshots, because it is designed to transmit multimedia content, supported by every smartphone, included in every wireless plan, and does not need any configuration. We have implemented the system on the Android platform and evaluated it using several smartphones. The experimental results show the system works effectively and takes less than one minute to gather forensic pictures.