Overcoming the obfuscation of Java programs by identifier renaming

Abstract

Decompilation is the process of translating object code to source code and is usually the first step towards the reverse-engineering of an application. Many obfuscation techniques and tools have been developed, with the aim of modifying a program, such that its functionalities are preserved, while its understandability is compromised for a human reader or the decompilation is made unsuccessful. Some approaches rely on malicious identifiers renaming, i.e., on the modification of the program identifiers in order to introduce confusion and possibly prevent the decompilation of the code. In this work we introduce a new technique to overcome the obfuscation of Java programs by identifier renaming. Such a technique relies on the intelligent modification of identifiers in Java bytecode. We present a new software tool which implements our technique and allows the processing of an obfuscated program in order to rename the identifiers as required by our technique. Moreover, we show how to use the existing tools to provide a partial implementation of the technique we propose. Finally, we discuss the feasibility of our approach by showing how to contrast the obfuscation techniques based on malicious identifier renaming recently presented in literature.