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Security and Communication Networks
Volume 2017, Article ID 3659167, 11 pages
Research Article

CHAOS: An SDN-Based Moving Target Defense System

1Key Laboratory of Aerospace Information Security and Trusted Computing, Ministry of Education, Computer School of Wuhan University, Wuhan, China
2Division of Computer Science, School of Computing, Clemson University, Clemson, SC 29634, USA

Correspondence should be addressed to Juan Wang; nc.ude.uhw@gnawj

Received 2 August 2017; Accepted 11 September 2017; Published 16 October 2017

Academic Editor: Zhiping Cai

Copyright © 2017 Yuan Shi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Moving target defense (MTD) has provided a dynamic and proactive network defense to reduce or move the attack surface that is available for exploitation. However, traditional network is difficult to realize dynamic and active security defense effectively and comprehensively. Software-defined networking (SDN) points out a brand-new path for building dynamic and proactive defense system. In this paper, we propose CHAOS, an SDN-based MTD system. Utilizing the programmability and flexibility of SDN, CHAOS obfuscates the attack surface including host mutation obfuscation, ports obfuscation, and obfuscation based on decoy servers, thereby enhancing the unpredictability of the networking environment. We propose the Chaos Tower Obfuscation (CTO) method, which uses the Chaos Tower Structure (CTS) to depict the hierarchy of all the hosts in an intranet and define expected connection and unexpected connection. Moreover, we develop fast CTO algorithms to achieve a different degree of obfuscation for the hosts in each layer. We design and implement CHAOS as an application of SDN controller. Our approach makes it very easy to realize moving target defense in networks. Our experimental results show that a network protected by CHAOS is capable of decreasing the percentage of information disclosure effectively to guarantee the normal flow of traffic.