CSCE 715: Network Systems Security

1. CSCE 715:Network Systems Security Chin-Tser Huang huangct@cse.sc.edu University of South Carolina

2. About Me • Chin-Tser Huang • Ph.D. in Computer Sciences, University of Texas at Austin • Research in network security, network protocol design and verification, distributed systems • My web page can be found at http://www.cse.sc.edu/~huangct (C) 2009 Chin-Tser Huang

3. About You • What’s your name? • Where are you from? • When did you join USC? • What are your research interests? (C) 2009 Chin-Tser Huang

4. About the Course • A grad-level course focusing on basics and issues in network security • First half will be lectures about elements of network security, cryptography backgrounds, and introduction to network security designs • Second half will be your chance to present what you have learned from key research papers (C) 2009 Chin-Tser Huang

5. Course Information Online • http://www.cse.sc.edu/~huangct/CSCE715S09/index.htm • List of assigned paper and useful links are available on the page • Lecture slides will be available online too (C) 2009 Chin-Tser Huang

6. Why Should You Take This Course • Security is an increasingly important issue • You want to have basic knowledge about network security • You can learn latest attacks and newest skills to counter those attacks • You have a chance to implement the skills learned in the class (C) 2009 Chin-Tser Huang

7. Your Best Strategy • Come to every lecture to learn basic security problems and skills to counter them • Keep yourself exposed to articles related to network security to collect project ideas • Read each assigned paper and write good summary for each paper • Do not wait till last minute to prepare for exam or work on project • Enjoy the fun! (C) 2009 Chin-Tser Huang

8. What Can Go Wrong… • …when your computer y receive or is waiting for a message m? ? Internet m x y (C) 2009 Chin-Tser Huang

9. Message Loss • Adversary A can discard m in its transit A m x y (C) 2009 Chin-Tser Huang

10. Message Interception • Adversary A can get a copy of m when m passes by m A m m x y (C) 2009 Chin-Tser Huang

11. Message Modification • Adversary A can arbitrarily modify the content of m to become m’ A m m’ x y (C) 2009 Chin-Tser Huang

12. Message Insertion • Adversary A can arbitrarily fabricate a message m, pretending that m was sent by x src: x dst: y A m x y (C) 2009 Chin-Tser Huang

13. Message Replay • Adversary A can replay a message m that has been sent earlier by x and received by y m A m x y (C) 2009 Chin-Tser Huang

14. … … … … … … Denial-of-Service Attack • Adversary A can send huge amount of messages to y to block m from arriving at y • In the case of botnet attack, the adversary instructs many bots to send messages to y simultaneously A m ????? x y (C) 2009 Chin-Tser Huang

15. More Scenarios • In one case, x wants y to be able to verify message m is sent by a legitimate party but not able to determine identity of x src: ? dst: y Internet m x y (C) 2009 Chin-Tser Huang

16. z x sent to y m More Scenarios • In another case, y wants to be able to prove to third party z that y receives message m from x Internet m x y (C) 2009 Chin-Tser Huang

17. Network Security Is Great… • Protect messages from interception in their transit • Provide desired level of privacy for user or data • Detect and discard messages that are modified, inserted, or replayed • Disallow unauthorized access to local system resource and sensitive data (C) 2009 Chin-Tser Huang

18. …But Hard To Achieve • Many layers in network architecture • Many different media of network connection • Adversary’s location hard to determine • New attacks keep emerging • Cryptographic overhead (C) 2009 Chin-Tser Huang

19. Next Class • Type of attacks • Network security services • Formal specification and verification of network protocols • Read Ch. 1 (C) 2009 Chin-Tser Huang