CoDisasm

Guillaume Bonfante, Jose Fernandez, Jean-Yves Marion, Benjamin Rouxel, Fabrice Sabatier, Aurélien Thierry
2015 Proceedings of the 22nd ACM SIGSAC Conference on Computer and Communications Security - CCS '15  
Fighting malware involves analyzing large numbers of suspicious binary files. In this context, disassembly is a crucial task in malware analysis and reverse engineering. It involves the recovery of assembly instructions from binary machine code. Correct disassembly of binaries is necessary to produce a higher level representation of the code and thus allow the analysis to develop high-level understanding of its behavior and purpose. Nonetheless, it can be problematic in the case of malicious
more » ... e, as malware writers often employ techniques to thwart correct disassembly by standard tools. In this paper, we focus on the disassembly of x86 selfmodifying binaries with overlapping instructions. Current state-of-the-art disassemblers fail to interpret these two common forms of obfuscation, causing an incorrect disassembly of large parts of the input. We introduce a novel disassembly method, called concatic disassembly, that combines CONCrete path execution with stATIC disassembly. We have developed a standalone disassembler called CoDisasm that implements this approach. Our approach substantially improves the success of disassembly when confronted with both self-modification and code overlap in analyzed binaries. To our knowledge, no other disassembler thwarts both of these obfuscations methods together.
doi:10.1145/2810103.2813627 dblp:conf/ccs/BonfanteFMRST15 fatcat:nmg5w4tktzckliwhg4qj5g65zm