Date of Award

5-2013

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Electrical Engineering

Advisor

Brooks, Dr. Richard R

Committee Member

Wang , Dr. Kuang-Ching

Committee Member

Walker , Dr. Ian

Abstract

Wireless communications is part of everyday life. As it is incorporated into new products and services, it brings additional security risks and requirements. A thorough understanding of wireless protocols is necessary for network administrators and manufacturers. Though most wireless protocols have strict standards, many parts of the hardware implementation may deviate from the standard and be proprietary. In these situations reverse engineering must be conducted to fully understand the strengths and vulnerabilities of the communication medium.
New 4G broadband wireless access protocols, including IEEE 802.16e and WiMAX, offer higher data rates and wider coverage than earlier 3G technologies. Many security vulnerabilities, including various Denial of Service (DoS) attacks, have been discovered in 3G protocols and the original IEEE 802.16 standard. Many of these vulnerabilities and new security flaws exist in the revised standard IEEE 802.16e. Most of the vulnerabilities already discovered allow for DoS attacks to be carried out on WiMAX networks. This study examines and analyzes a new DoS attack on IEEE 802.16e standard. We investigate how system parameters for the WiMAX Bandwidth Contention Resolution (BCR) process affect network vulnerability to DoS attacks. As this investigation developed and transitioned into analyzing hardware implementations, reverse engineering was needed to locate and modify the BCR system parameters.
Controlling the BCR system parameters in hardware is not a normal task. The protocol allows only the BS to set the system parameters. The BS gives one setting of the BCR system parameters to all WiMAX clients on the network and everyone is suppose to follow these settings. Our study looks at what happens if a set of users, attackers, do not follow the BS's settings and set their BCR system parameters independently. We hypothesize and analyze different techniques to do this in hardware with the goal being to replicate previous software simulations that looked at this behavior.
This document details our approaches to reverse engineer IEEE 802.16e and WiMAX. Additionally, we look at network security analysis and how to design experiments to reduce time and cost. Factorial experiment design and ANOVA analysis is the solution. In using these approaches, one can test multiple factors in parallel, producing robust, repeatable and statistically significant results. By treating all other parameters as noise when testing first order effects, second and third order effects can be analyzed with less significance. The details of this type of experimental design is given along with NS-2 simulations and hardware experiments that analyze the BCR system parameters. This purpose of this paper is to serve as guide for reverse engineering network protocols and conducting network experiments.
As wireless communication and network security become ubiquitous, the methods and techniques detailed in this study become increasingly important. This document can serve as a guide to reduce time and effort when reverse engineering other communication protocols and conducting network experiments.

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