Countering type confusion and buffer overflow attacks on Java smart cards by data type sensitive obfuscation

Abstract

Java enabled smart cards protect security-related code and data by a sandbox concept. Unfortunately, this sandbox can be bypassed by fault attacks. Therefore, there is a substantial need for transparent, effective, and low-overhead countermeasures. This work demonstrates a new countermeasure against type confusion and buffer overflow attacks. This new countermeasure is based on obfuscating the security critical calculation parts of a virtual machine by secret keys. This countermeasure was integrated into a Java Card virtual machine running on a smart card prototype. New hardware features were added to this prototype to accelerate the obfuscating operation. The execution time overhead of the new countermeasure is demonstrated by performing run-time measurements on the prototype.