Automatically Securing Permission-Based Software by Reducing the Attack Surface: An Application to Android

A common security architecture, called the permission-based security model (used e.g. in Android and Blackberry), en- tails intrinsic risks. For instance, applications can be granted more permissions than they actually need, what we call a "permission gap". Malware can leverage the unused permis- sions for achieving their malicious goals, for instance using code injection. In this paper, we present an approach to de- tecting permission gaps using static analysis. Our prototype implementation in the context of Android shows that the static analysis must take into account a significant amount of platform-specific knowledge. Using our tool on two datasets of Android applications, we found out that a non negligible part of applications suffers from permission gaps, i.e. does not use all the permissions they declare.