Bunshin: Compositing Security Mechanisms through Diversification


Meng Xu, Kangjie Lu, Taesoo Kim, and Wenke Lee, Georgia Institute of Technology


A number of security mechanisms have been proposed to harden programs written in unsafe languages, each of which mitigates a specific type of memory error. Intuitively, enforcing multiple security mechanisms on a target program will improve its overall security. However, this is not yet a viable approach in practice because the execution slowdown caused by various security mechanisms is often non-linearly accumulated, making the combined protection prohibitively expensive; further, most security mechanisms are designed for independent or isolated uses and thus are often in conflict with each other, making it impossible to fuse them in a straightforward way.

In this paper, we present BUNSHIN, an N-version-based system that enables different and even conflicting security mechanisms to be combined to secure a program while at the same time reducing the execution slowdown. In particular, we propose an automated mechanism to distribute runtime security checks in multiple program variants in such a way that conflicts between security checks are inherently eliminated and execution slowdown is minimized with parallel execution. We also present an N-version execution engine to seamlessly synchronize these variants so that all distributed security checks work together to guarantee the security of a target program.

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@inproceedings {203267,
author = {Meng Xu and Kangjie Lu and Taesoo Kim and Wenke Lee},
title = {Bunshin: Compositing Security Mechanisms through Diversification},
booktitle = {2017 USENIX Annual Technical Conference (USENIX ATC 17)},
year = {2017},
isbn = {978-1-931971-38-6},
address = {Santa Clara, CA},
pages = {271--283},
url = {https://www.usenix.org/conference/atc17/technical-sessions/presentation/xu-meng},
publisher = {USENIX Association},
month = jul,

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