Detecting a multi-homed device using clock skew

The aim of this thesis was to determine the feasibility of identifying a device connected to the Internet through multiple interfaces (i.e., multi-homed) using only the information provided by passively observing network traffic. Since multi-homed hosts allow an alternate means for outside entities to circumvent the security of a firewall and gain access to a network, it is important for a network's security to be able to detect and remove such devices. In this work, the idea of using clock skew—which is the difference in perceived time between two system clocks—as a unique signature is utilized to identify hosts on a network that are potentially multi-homed. Testing was done on a software-defined network that contained a multi-homed host. After traffic between hosts was collected and analyzed, analysis of the confidence intervals of the device's clock skew was conducted to determine if IP addresses originating from the same host could be successfully detected solely from network traffic. Testing confirmed that the proposed scheme provided a valid means of detecting a multi-homed device on a network. This scheme was repeated on multiple hosts and on a device with multiple connections to the network. http://archive.org/details/detectingmultiho1094550588 Lieutenant, United States Navy Approved for public release; distribution is unlimited.