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

Android based devices are becoming widespread. As a result and since those devices contain personal and confidential data, the security model of the android software stack has been analyzed extensively. One key feature of the security model is that applications must declare a list of permissions they are using to access resources. Using static analysis, we first extracted a table from the Android API which maps methods to permissions. Then, we use this mapping within a tool we developed to check that applications effectively need all the permissions they declare. Using our tool on a set of android applications, we found out that a non negligible part of the applications do not use all the permissions they declare. Consequently, the attack surface of such applications can be reduced by removing the non-needed permissions.