Privacy Preserving Watchdog System in Android Systems

Recently, rise of smartphone use for daily activities is phenomenal and the security of mobile platforms is receiving great attention by the security community. Unlike servers and workstations, the mobile system deals with personal information including locations, emails, social activities, and even photos. Therefore, privacy concern is the most important matter to every user. Many adversarial attempts install malicious Apps in the victim's smartphone and steal sensitive information. This work focuses on detecting such stealthy access to the information in the smartphone. In particular, we monitor Apps' activities in a level of system call. We also built a privacy policy engine and policy enforcement mechanism. We propose a novel approach that allows fine-grained privacy level control by modifying the parameters and return values of a system call on-line. We demonstrate the feasibility of the watchdog service in two privacy- sensitive scenarios: location-sharing and photo-sharing.