Enhancing Security by Diversifying Instruction Sets

Despite the variety of choices regarding hardware and software, to date a large number of computer systems remain identical. Characteristic examples of this trend are Windows on x86 and Android on ARM. This homogeneity, sometimes referred to as “computing oligoculture", provides a fertile ground for malware in the highly networked world of today. One way to counter this problem is to diversify systems so that attackers cannot quickly and easily compromise a large number of machines. For instance, if each system has a different ISA, the attacker has to invest more time in developing exploits that run on every system manifestation. It is not that each individual attack gets harder, but the spread of malware slows down. Further, if the diversified ISA is kept secret from the attacker, the bar for exploitation is raised even higher. In this paper, we show that system diversification can be realized by enabling diversity at the lowest hardware/software interface, the ISA, with almost zero performance overhead. We also describe how prac- tical development and deployment problems of diversified systems can be handled easily in the context of popular software distrbution models, such as the mobile app store model. We demonstrate our proposal with an OpenSPARC FPGA prototype