Automated Multi-Layered Bytecode Generation for Preventing Sensitive Information Leaks From Android Applications

Sensitive information leakages from applications are a critical issue in the Android ecosystem. Despite the advance of techniques to secure applications such as packing and obfuscation, a lot of applications are still under the threat of repackaging attacks that inject malicious code and re-distribute applications. Also, as we are becoming more dependent on mobile technologies, more sensitive information is used on our mobile devices. Hence, it is of great importance to reduce the risk of such sensitive information leaks. In this paper, we first present a threat model that attempts to leak users' sensitive information by using the repackaging attack, named ReMaCi attack. By analyzing the top 8,546 applications downloaded from Google Play Store, we show that 50% of them are really vulnerable to the ReMaCi attack. We, thus, propose a novel, automated static anti-analysis tool, called AmpDroid, for preventing sensitive information leaks. AmpDroid identifies sensitive dataflows and isolates the code that handles the sensitive data from an application. To demonstrate the effectiveness of AmpDroid, we perform the security and performance evaluation of AmpDroid, comparing it with other obfuscation tools.