A detection framework for semantic code clones and obfuscated code

Code obfuscation is a staple tool in malware creation where code fragments are altered substantially to make them appear different from the original, while keeping the semantics unaffected. A majority of the obfuscated code detection methods use program structure as a signature for detection of unknown codes. They usually ignore the most important feature, which is the semantics of the code, to match two code fragments or programs for obfuscation. Obfuscated code detection is a special case of the semantic code clone detection task. We propose a detection framework for detecting both code obfuscation and clone using machine learning. We use features extracted from Java bytecode dependency graphs (BDG), program dependency graphs (PDG) and abstract syntax trees (AST). BDGs and PDGs are two representations of the semantics or meaning of a Java program. ASTs capture the structural aspects of a program. We use several publicly available code clone and obfuscated code datasets to validate the effectiveness of our framework. We use different assessment parameters to evaluate the detection quality of our proposed model. Experimental results are excellent when compared with contemporary obfuscated code and code clone detectors. Interestingly, we achieve 100% success in detecting obfuscated code based on recall, precision, and F1-Score. When we compare our method with other methods for all of obfuscations types, viz, contraction, expansion, loop transformation and renaming, our model appears to be the winner. In case of clone detection our model achieve very high detection accuracy in comparison to other similar detectors. (C) 2017 Elsevier Ltd. All rights reserved.