1. An Overview of Security Issues in Sensor Network
Presented by : Md. Iftekhar Salam

2. Presentation Outline Introduction to Sensor Network Justification
Security Requirements
Security Issues
Challenges
Conclusion

3. Introduction Wireless Sensor Network (WSN)
Consist of a large number of independent sensor nodes
Each sensor node is equipped with sensing, data processing, communicating device

4. Introduction… Applications Military Applications
Environmental Applications
Health Applications
Home Applications

5. Justification
WSNs are becoming a cost effective, practical way to go about deploying sensor networks.
Large range of applications from civilian to military purposes.
Security in WSNs are more complicated due to their deployment scenario and resource limitations… and thus more studies need to address the security issue

6. Security Requirements
Confidentiality
Availability
Integrity
Authentication
Non-repudiation
Freshness

7. Threats and Attacks External Attacks Internal Attacks
Passive attack – Involve unauthorized “listening” to the routing packets. Can be eased by using encryption.
Active attack – Introduce some denial of service attacks such as jamming, power exhaustion. Can be eased by providing authentication and integrity. Spread spectrum communication or frequency hopping is required to prevent jamming
Internal Attacks
Node compromise leads to the internal attack.
Compromised node may launch attack from different layers of the network protocol stack
Hard to be detected and prevented

8. Security Issues Physical Layer
Major attack in this layer includes jamming, capturing and tampering
Defense against jamming – spread spectrum or frequency hopping communication, switching to low duty cycle and conserving as much power as possible, locating jamming area and rerouting traffic, adopting prioritized transmission schemes to minimize collisions etc
Defense against tampering – Passive protection and Active protection
Passive Protection - Do not require energy and extra circuitry (protecting coatings, tamper seals)
Active Protection - Requires extra circuitry in the sensor node to protect sensitive data

9. Security Issues … Data Link Layer
Responsible for multiplexing of data streams, data frame detection, medium access and error control
Major attack includes collision, exhaustion and unfairness
Defense method includes
Error correcting code
TDMA
Rate limiting in MAC admission control

10. Security Issues … Network Layer
Responsible for end to end packet delivery
Major Attacks :
Spoofing, altering or replayed routing information, selective forwarding, sinkhole attacks, Sybil attacks, worm-holes, Hello flood attacks
Impose significant challenges to secure routing protocol design
Defense:
Encryption and authentication, multipath routing, identity verification, bidirectional link verification, authentication broadcast.

11. Security Issues … Transport Layer
Provide transparent transfer of data between end users, providing reliable data transfer services to the upper layers
Major attack includes flooding and desynchronization
Countermeasures include solving client puzzles, authentication

12. Security Issues… Summary
OSI Model
Attacks
Defense Method
Physical Layer
Jamming, tampering
Spread spectrum , passive protection, active protection
Data Link Layer
Collision, exhaustion and unfairness are the major attacks.
Error correcting code, TDMA, rate limiting in MAC access control
Network Layer
Spoofing, altering information, selective forwarding, sinkhole attacks, Sybil attacks, worm-holes
Encryption and authentication, multipath routing, identity verification, authentication broadcast
Transport Layer
Flooding, desynchronization
client puzzles, authentication

13. Conclusion
Security aspects of sensor network very important and under intense research
Tradeoff between resource consumption and security
Design and implementation of an efficient mechanism for node compromise detection
Secure routing protocol design

14. References
1. X. Chen, K. Makki, K. Yen, and N. Pissinou, “Sensor Network Security: A Survey”, IEEE COMMUNICATIONS SURVEYS & TUTORIALS, VOL. 11, NO. 2, SECOND QUARTER 2009

15. Thank You