Compositional Taint Analysis of Native Codes for Security Vetting of Android Applications

Security vetting of Android applications is one of the crucial aspects of the Android ecosystem. Regarding the state of the art tools for this goal, most of them doesn't consider analyzing native codes and only analyze the Java code. However, Android concedes its developers to implement a part or all of their applications using C or C++ code. Thus, applying conservative manners for analyzing Android applications while ignoring native codes would lead to less precision in results. Few works have tried to analyze Android native codes, but only JN-SAF has applied taint analysis using static techniques such as symbolic execution. However, symbolic execution has some problems when is used in large programs. One of these problems is the exponential growth of program paths that would raise the path explosion issue. In this work, we have tried to alleviate this issue by introducing our new tool named CTAN. CTAN applies new symbolic execution methods to angr in a particular way that it can make JN-SAF more efficient and faster. We have introduced compositional taint analysis in CTAN by combining satisfiability modulo theories with symbolic execution. Our experiments show that CTAN is 26 percent faster than its previous work JN-SAF and it also leads to more precision by detecting more data-leakage in large Android native codes.