Implementation of network moving target defense in embedded systems
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Moving target defense provides opportunities for adaptive defense in embedded systems. A great deal of work has been done on incorporating moving target defense techniques into enterprise systems to increase the cost to attackers and level the playing field. A smaller body of work focuses on implementing these techniques in embedded systems, which can greatly benefit from adaptive self-defense techniques. This work implements a network shuffling proof of concept in the Zephyr real time operating system to tackle the challenge of incorporating shuffling techniques into embedded systems. A host-centric, high security implementation is provided which maximizes attacker uncertainty and minimizes the impact of host compromise. Identifiers are utilized at the datalink, network, and transport layers and rotated per connection using keys shared between host pairs.Existing shuffling schemes are explored, including those targeted to IoT contexts. Existing limitations in protecting embedded systems are considered along with the presented by moving target defense. The design details and implementation of incorporating a moving target defense module to in the Zephyr networking stack is provided. The protection provided by the scheme is evaluated and it is compared to existing address shuffling schemes. Future work in better handling data forwarding and collisions in the proof of concept scheme are considered. Options for adapting and building on the scheme to meet the needs of system designers are explored. This work provides system designers with insights into implementing address shuffling in embedded systems.