Poster: Sdguard: An Android Application Implementing Privacy Protection and Ransomware Detection.

Currently, the smartphone has become an essential communication and amusement tool, which has strong computing power and a variety of functions. Especially, the market share of smartphone with android system account for 84% in 2016[1]. Under android system, a large of privacy data (e.g. photos or videos) are stored in external storage (emulated Sdcard storage), which can be accessed by installed apps. This not only results in privacy leakage but also incurs ransomware attack[2] (e.g. simplocker). Therefore, we present Sdguard, an app, can implement fine-grain permission control based on Linux DAC mechanism and detect ransomware which encrypts content of file stored in external storage or lock user screen. To install Sdguard app, we need to ensure that the smartphone has been rooted and use FUSE filesystem on external storage. During installing, sdcard daemon of android (i.e. FUSE daemon) is replaced by our customized sdcard daemon. After rebooting system, the customized daemon is loaded, and each component of Sdguard is running.