R-Droid constitutes a novel slice-optimization approach to leverage static analysis of Android applications. Building on top of precise application lifecycle models, we employ a slicing-based analysis to generate data-dependent statements for arbitrary points of interest in an application. As a result of our optimization, the produced slices are, on average, 49% smaller than standard slices, thus facilitating code understanding and result validation by security analysts. Moreover, by re-targeting strings, our approach enables automatic assessments for a larger number of use-cases than prior work.
On a large-scale data-leak analysis on a set of 22,700 Android apps from Google Play, R-Droid managed to identify a significantly larger set of potential privacy-violating information flows than previous work, including 2,157 sensitive flows of password-flagged UI widgets in 256 distinct apps.
In contrast to the Android application layer, Android's application framework's internals and their influence on the platform security and user privacy are still largely a black box for us. In this paper, we establish a static runtime model of the application framework in order to study its internals and provide the first high-level classification of the framework's protected resources. We thereby uncover design patterns that differ highly from the runtime model at the application layer.
We demonstrate the benefits of our insights for security-focused analysis of the framework by re-visiting the important use-case of mapping Android permissions to framework/SDK API methods. We, in particular, present a novel mapping based on our findings that significantly· improves on prior results in this area that were established based on insufficient knowledge about the framework's internals. Moreover, we introduce the concept of permission locality to show that although framework services follow the principle of separation of duty, the accompanying permission checks to guard sensitive operations violate it.
Find permission mappings and other data on https://github.com/reddr/axplorer
We propose LibScout, a library detection technique that is resilient against common code obfuscations and that is capable of pinpointing the exact library version used in apps. Libraries are detected with profiles from a comprehensive library database that we generated from the original library SDKs. We apply our technique to the top apps on Google Play and their complete histories to conduct a longitudinal study of library usage and evolution in apps.
Find more information and the source-code on https://github.com/reddr/LibScout
Research area: Mobile security
Master's Thesis: Verifying the Internet Access of Android Applications
Bachelor's Thesis: Improving token-based HTTP anomaly detection in web applications