| With the rise of mobile technologies in recent years, smart mobile devices, such as smartphones and tablet computers, have become an integral part of people's daily lives. Like traditional cell phones, smartphones can be used for phone calls and text messaging. Driven by recent innovations, current smartphones have also become media players, GPS systems, digital cameras, portable gaming consoles, and Web browsers. The capabilities and functionalities of smart mobile devices have been significantly expanded by the large number of third-party applications. As we witness a phenomenal growth in the number and variety of mobile applications, their usage has become increasingly prevalent, yet we lack a systematic understanding of this emerging, important software ecosystem.;This dissertation presents novel, general techniques and tools for analyzing and understanding mobile applications. It focuses on analyzing applications on the Android operating system, which is currently the most popular mobile platform. This dissertation presents the first large-scale, systematic study of third-party Android applications from the Google Play Store. By investigating unique characteristics of Android applications, it uncovers and provides insights into common errors and pitfalls during application development and provides actionable recommendations where applicable. This dissertation also presents Heimdall, a static analysis framework that automatically tracks the flow of sensitive information in Android applications. Heimdall has been used to uncover potentially unsafe flows of sensitive information on a large scale, providing a comprehensive understanding of privacy-sensitive information usage in third-party Android applications. The findings presented in this dissertation benefit the whole Android community, from platform and tool developers to application developers and end-users. |
