A Framework to Secure the Development and Auditing of SSL Pinning in Mobile Applications: The Case of Android Devices

The use of mobile devices has undergone rapid growth in recent years. However, on some occasions, security has been neglected when developing applications. SSL/TLS has been used for years to secure communications although it is not a vulnerability-free protocol. One of the most common vulnerabilities is SSL pinning bypassing. This paper first describes some security controls to help protect against SSL pinning bypassing. Subsequently, some existing methods for bypassing are presented and two new methods are defined. We performed some experiments to check the use of security controls in widely used applications, and applied SSL pinning bypassing methods. Finally, we created an applicability framework, relating the implemented security controls and the methods that are applicable. This framework provides a guideline for pentesters and app developers.