SplitSecond: Flexible Privilege Separation of Android Apps Android applications have been attractive targets to attackers due to the large number of users and the sensitive information they possess. After the success of the first step of an attack exploiting a software vulnerability, the consequential damage is primarily determined by the criticality and the amount of Android permissions that a victim application has. As a countermeasure, process separation techniques that isolate potentially vulnerable components  usually native libraries  from the critical data and permissions, have been proposed. However, existing techniques offer little flexibility in the separation, e.g., with all native code being placed into one process without considering its dependency with other (Java) components and the nonempty set of permissions needed. In this paper, we propose a flexible privilege separation system, named SplitSecond, that enables selective permission separation at the granularity of Java components and native methods. SplitSecond provides safety against the attacks by restricting permissions on a user selectable isolation unit. According to our case study and experimental evaluation on a real handset with SplitSecond adopted Android OS and 100 topranked Android applications, 59.59% of activities, 66.8% of native methods, and 47.49% of permissions on average are flexibly splittable by SplitSecond with moderate overhead.

Automatic Components Separation of Obfuscated Android Applications: An Empirical Study of Design Based Features In modern days, mobile applications (apps) have become omnipresent. Components of mobile apps (such as 3rd party libraries) require to be separated and analyzed differently for security issue detection, repackaged app detection, tumor code purification and so on. Various techniques are available to automatically analyze mobile apps. However, analysis of the appu0027s executable binary remains challenging due to required curated database, large codebases and obfuscation. Considering these, we focus on exploring a versatile technique to separate different components with designbased features independent of code obfuscation. Particularly, we conducted an empirical study using design patterns and fuzzy signatures to separate app components such as 3rd party libraries. In doing so, we built a system for automatically extracting design patterns from both the executable package (APK) and Jar of an Android application. The experimental results with various standard datasets containing 3rd party libraries, obfuscated apps and malwares reveal that design features like these are present significantly within them (within 60% APKs including malware). Moreover, these features remain unaltered even after app obfuscation. Finally, as a case study, we found that the design patterns alone can detect 3rd party libraries within the obfuscated apps considerably (F1 score is 32%). Overall, our empirical study reveals that design features might play a versatile role in separating various Android components for various purposes.