Wireless Sensor Networks Security

1. Wireless Sensor Networks Security Lindsey McGrath and Christine Weiss

2. Agenda • Introduction • Background - Problem Statement • Requirements for Sensor Network Security • Attacks on Sensor Networks • Security Services • Challenges • Conclusion

3. Introduction • What is a Sensor Network ? • A heterogeneous system combining tiny sensors and actuators with general-purpose computing elements. Most consisting of hundreds or thousands of low-power, low-cost nodes deployed to monitor and affect the environment. • What are they used for? • Ocean and wildlife monitoring. • Monitoring of manufactured machinery. • Building safety. • Earthquake monitoring. • Variety of military applications. • Medical monitoring and research. • Addressing Sensor Network Security…existing security mechanisms are inadequate! What are the security issues? What security services will work?

4. Background-Problem Statement • Network Assumptions • Insecure links – non denial of eavesdropping. • Replay and injection of packets. • Non tamper resistant. • Trust Requirements • Base station and aggregation point trustworthiness. • Threat Models • Outsider vs. insider attacks. • Mote-class vs. laptop-class attackers. • Security Goals • Integrity, authentication, freshness and confidentiality.

5. Requirements for WSN Security • Data Confidentiality – omission of data leaks to neighboring networks. • Data Authentication – verification of sender/receiver. • Data Integrity – non altered transmission of data. • Data Freshness – ensuring data is recent while allowing for delay estimation.

6. Attacks on WSN • Spoofed, altered and replayed routing information • Selective Forwarding • Sinkhole attacks • The Sybil attack • Wormholes

7. Security Services • Link-layer encryption and authentication • Multi-path routing • Identity verification • Bidirectional link verification • Authenticated broadcasts

8. Challenges • The existing infrastructure is already resource-starved. • Communication bandwidth • Power • Computational power • Preventing insider attacks. • Sinkhole attacks and wormholes – no known countermeasures to apply after the protocol is designed. • Building multi-hop routing topology - Nodes within one or two hops of the base station are attractive to intruders.

9. Conclusion • Currently proposed routing protocols for WSNs are insecure but vital. • Link layer encryption and authentication mechanisms provide reasonable defense for mote-class outsider attacks. • Cryptography is inefficient in preventing against laptop-class and insider attacks. • Remains an open problem for additional research and development.

10. Resources • Perrig, A., Stankovic, J., and Wagner, D. 2004. Security in wireless sensor networks. Commun. ACM 47, 6 (Jun. 2004), 53-57. • Perrig, A., Szewczyk, R., Tygar, J. D., Wen, V., and Culler, D. E. 2002. SPINS: security protocols for sensor networks. Wirel. Netw. 8, 5 (Sep. 2002), 521-534. • Karlof, C. and Wagner, D. Secure routing in wireless sensor networks: Attacks and countermeasures. In Proceedings of the 1st IEEE International Workshop on Sensor Network Protocols and Applications (Anchorage, AK, May 11, 2003). • Hu, Y.-C., Perrig, A., and Johnson, D. Packet leashes: A defense against wormhole attacks in wireless ad hoc networks. In Proceedings of IEEE Infocom 2003 (San Francisco, Apr. 1--3, 2003). • L. Zhou and Z. Haas, “Securing ad hoc networks,” IEEE NetworkMagazine, vol. 13, no. 6, November/December 1999. • Y.-C. Hu, A. Perrig, and D. B. Johnson, “Wormhole detection in wireless ad hoc networks,” Department of Computer Science, Rice University, Tech. Rep. TR01-384, June 2002.