Shuffler: Fast and Deployable Continuous Code Re-Randomization


David Williams-King and Graham Gobieski, Columbia University; Kent Williams-King, University of British Columbia; James P. Blake and Xinhao Yuan, Columbia University; Patrick Colp, University of British Columbia; Michelle Zheng, Columbia University; Vasileios P. Kemerlis, Brown University; Junfeng Yang, Columbia University; William Aiello, University of British Columbia


While code injection attacks have been virtually eliminated on modern systems, programs today remain vulnerable to code reuse attacks. Particularly pernicious are Just-In-Time ROP (JIT-ROP) techniques, where an attacker uses a memory disclosure vulnerability to discover code gadgets at runtime. We designed a code-reuse defense, called Shuffler, which continuously re-randomizes code locations on the order of milliseconds, introducing a real-time deadline on the attacker. This deadline makes it extremely difficult to form a complete exploit, particularly against server programs that often sit tens of milliseconds away from attacker machines.

Shuffler focuses on being fast, self-hosting, and nonintrusive to the end user. Specifically, for speed, Shuffler randomizes code asynchronously in a separate thread and atomically switches from one code copy to the next. For security, Shuffler adopts an “egalitarian” principle and randomizes itself the same way it does the target. Lastly, to deploy Shuffler, no source, kernel, compiler, or hardware modifications are necessary.

Evaluation shows that Shuffler defends against all known forms of code reuse, including ROP, direct JITROP, indirect JIT-ROP, and Blind ROP. We observed 14.9% overhead on SPEC CPU when shuffling every 50 ms, and ran Shuffler on real-world applications such as Nginx. We showed that the shuffled Nginx scales up to 24 worker processes on 12 cores.

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@inproceedings {199297,
author = {David Williams-King and Graham Gobieski and Kent Williams-King and James P. Blake and Xinhao Yuan and Patrick Colp and Michelle Zheng and Vasileios P. Kemerlis and Junfeng Yang and William Aiello},
title = {Shuffler: Fast and Deployable Continuous Code Re-Randomization},
booktitle = {12th {USENIX} Symposium on Operating Systems Design and Implementation ({OSDI} 16)},
year = {2016},
isbn = {978-1-931971-33-1},
address = {Savannah, GA},
pages = {367--382},
url = {},
publisher = {{USENIX} Association},