Since more than 96 percent of mobile malware targets the Android platform, various techniques based on static code analysis or dynamic behavior analysis have been proposed to detect malicious apps. As malware is becoming more complicated and stealthy, recent research proposed a promising detection approach that looks for the inconsistency between an app's permissions and its description. In this paper, we first revisit this approach and reveal that using description and permission will lead to many false positives because descriptions often fail to declare all sensitive operations. Then, we propose exploiting an app's privacy policy and its bytecode to enhance the malware detection based on description and permissions. It is non-trivial to automatically analyze privacy policy and perform the cross-verification among these four kinds of software artifacts including, privacy policy, bytecode, description, and permissions. To address these challenging issues, we first propose a novel data flow model for analyzing privacy policy, and then develop a new system, named TAPVerifier, for carrying out investigation of individual software artifacts and conducting the cross-verification. The experimental results show that TAPVerifier can analyze privacy policy with a high accuracy and recall rate. More importantly, integrating privacy policy and bytecode level information can remove up to 59.4 percent false alerts of the state-of-the-art systems, such as AutoCog, CHABADA, etc.

More and more app developers use the packing services (or packers) to prevent attackers from reverse engineering and modifying the executable (or Dex files) of their apps. At the same time, malware authors also use the packers to hide the malicious component and evade the signature-based detection. Although there are a few recent studies on unpacking Android apps, it has been shown that the evolving packers can easily circumvent them because they are not adaptive to the changes of packers. In this paper, we propose a novel adaptive approach and develop a new system, named PackerGrind, to unpack Android apps. We also evaluate PackerGrind with real packed apps, and the results show that PackerGrind can successfully reveal the packers' protection mechanisms and recover the Dex files with low overhead, showing that our approach can effectively handle the evolution of packers.

Many apps have been developed to measure the performance of mobile networks. Unfortunately, their measurement results may not be what users expect, because the results could be biased by various factors and the apps' descriptions may confuse users. Although a few recent studies pointed out several factors, they missed other important factors and lacked of finegrained analysis on the factors and measurement apps. Moreover, none has studied whether or not the descriptions of such apps will mislead users. In this paper, we conduct the first systematic study of the factors that could bias the result from measurement apps and their descriptions. We identify new factors, revisit known factors, and propose a novel approach with new tools to discover these factors in proprietary apps. We also develop a new measurement app named MobiScope for demonstrating how to mitigate the negative effects of these factors. Furthermore, we construct enhanced descriptions for measurement apps to provide users more information about what is measured. The extensive experimental results illustrate the negative effects of various factors, the improvement in performance measurement brought by MobiScope, and the clarity of the enhanced descriptions.

Since more than 96% of mobile malware targets on Android platform, various techniques based on static code analysis or dynamic behavior analysis have been proposed to detect malicious applications. As malware is becoming more complicated and stealthy, recent research proposed a promising detection approach that looks for the inconsistency between an application's permissions and its description. In this paper, we revisit this approach and find that using description and permission will lead to many false positives. Therefore, we propose employing app's privacy policy and its bytecode to enhance description and permission for malware detection. It is non-trivial to automatically analyze privacy policy and perform the cross-verification among these four kinds of software artifacts including, privacy policy, bytecode, description, and permissions. We propose a novel data flow model for analyzing privacy policy, and develop a novel system, named TAPVerifier, for carrying out investigation of individual software artifacts and conducting the cross-verification. The experimental results show that TAPVerifier can analyze privacy policy with a high accuracy and recall rate. More importantly, integrating privacy policy and code level information removes 8.1%-65.5% false positives of existing systems based on description and permission.