Smart cards are the safer device to execute cryptographic algorithms. Applications are verified before being loaded into the card. Recently, the idea of combined attacks to bypass byte code verification has emerged. Indeed, correct and legitimate Java Card applications can be dynamically modified on-card using a laser beam to become mutant applications or fault enabled viruses. We propose a framework for manipulating binary applications to design viruses for smart cards. We present development, experimentation and an example of this kind of virus.