In Android systems, an attacker can obfuscate an application code to leak sensitive information. TaintDroid is an information flow tracking system that protects private data in smartphones. But, TainDroid cannot detect control flows. Thus, it can be circumvented by an obfuscated code attack based on control dependencies. In this paper, we present a collection of obfuscated code attacks on TaintDroid system. We propose a technical solution based on a hybrid approach that combines static and dynamic analysis. We formally specify our solution based on two propagation rules. Finally, we evaluate our approach and show that we can avoid the obfuscated code attacks based on control dependencies by using these propagation rules.