A generic attack on checksumming-based software tamper resistance

Self-checking software tamper resistance mechanisms employing checksums, including ad-vanced systems as recently proposed by Chang and Atallah (2002) and Horne et al. (2002), have been promoted as an alternative to other software integrity verification techniques. Ap-pealing aspects include the promise of being able to verify the integrity of software independent of the external support environment, as well as the ability to automatically integrate check-summing code during program compilation or linking. In this paper, we show that the rich functionality of many modern processors, including UltraSparc and x86-compatible processors, facilitates automated attacks which defeat such checksumming by self-checking programs.