SEMEO: A Semantic Equivalence Analysis Framework for Obfuscated Android Applications

Software repackaging is a common approach for creating malware. Malware authors often use software repackaging to obfuscate code containing malicious payloads. This forces analysts to spend a large amount of time filtering out benign obfuscated methods in order to locate potentially malicious methods for further analysis. If an effective mechanism for filtering out benign obfuscated methods were available, the number of methods that analysts must consider could be reduced, allowing them to be more productive. In this paper, we present SEMEO, an obfuscation-resilient approach for semantic equivalence analysis of Android apps. SEMEO automatically and with high accuracy determines whether a repackaged and obfuscated version of a method is semantically equivalent to an original version thereof. SEMEO further handles widely-used and complicated types of obfuscations, as well as the scenarios where multiple obfuscation types are applied in tandem. Our empirical evaluation corroborates that SEMEO significantly outperforms the state-of-the-art, achieving 100% precision in identifying semantically equivalent methods across almost all apps under analysis. SEMEO consistently provides over 80% recall when one or two types of obfuscation are used and 73% recall when five different types of obfuscation are compositely applied.