An Adaptive Android Security Extension against Privilege Escalation Attacks

Android is the world's most popular mobile platform. Nevertheless, in spite of continuous efforts on its permission system, it is still incapable of resisting privilege escalation attacks, specially, the confused deputy attacks on numerous poor-designed applications. Worse yet, most existing security solutions become costly or rigid in recent Android dynamic permission environment. In this paper, we proposed a flexible and efficient security extension to Android middleware for protecting the vulnerable privileged applications from being abused by malwares in the dynamic permission scenario. Our framework maintains fresh permission states of applications at runtime and enforces access control on inter-component communications conservatively by checking the capability differences between applications, so as to provide more precise and temperate protection for applications. Moreover, we also introduced an efficient cache mechanism together with an optimized proactive updating method for decisions, which contributes significantly to improving the inspection efficiency. Finally, experimental results reveal that our framework is effective and adaptable in defending against confused deputy attacks on applications with negligible overhead and limited impact on application usability.