Security in GSM Networks Project Team: Sunil Alluri – [email protected] Sudha Kode – [email protected] Shilpa Prabhakar Reddy – [email protected] Introduction GSM: Global System for Mobile Communication: In spite of GSM being a widely deployed digital standard around the world it has some hidden weaknesses when concerned with the security issues. Previously it was believed that security can be achieved through obscurity, so the algorithms were not revealed to the public. But with ages, as the topic of security has become widely open with the security algorithms being exposed to the public, it has been proved that if given enough time and resources, the so called secured algorithms used in GSM networks are no longer secure. The major issues concerned with security in GSM networks are authentication, key generation and end-to-end data encryption over air. Multiple algorithms like A5, A3 and A8 are used to address all the security issues. Though the initial versions of these algorithms have been broken, these algorithms are revised every two years and the required changes are made to make them more secure against possible attacks. In addition to the brute force attack which is the most common attack to retrieve the keys, there are many kinds of attacks to which the GSM networks are highly vulnerable. Main focus of our project is on analyzing possible attacks and the counter measures taken to overcome these attacks with primary importance given to end-to-end encryption. We will also discuss briefly about the functioning of these algorithms and on which part of the network they are actually implemented. Project Specification: - The objective of our report is to provide a detailed insight of  GSM security architecture  Security algorithms implemented with in the GSM network(A3,A5,A8)  Various kinds of possible attacks in GSM networks  Brute-Force attack  Birthday attack Man-in-middle attack  Retrieving key over air  Cloning  Side channel attacks  False Base Station attacks  SMS viruses  Security Service provided by GSM  Anonymity  Authentication  User Data and signaling protection  The key management and authentication issues involved  Over the air transmission encryption. Tentative list of questions that we are seeking answer • Are the proposed algorithms in GSM network sufficient to fulfill all the security requirements? • What are the security issues that are not sufficiently handled by the existing GSM network? • What are the security measures that can be integrated into the present GSM network? • Are there any other alternative security algorithms that can be used in GSM networks? • How can end to end security be achieved in future? Format and tentative table of contents • Abstract of the proposed study. • Very brief description on security architecture of the GSM networks, analysis of algorithms used for security and the possible attacks on them. • Possible improvements in the architecture and algorithms, to ensure end to end encryption of the network. • Conclusion and expected future work. • References Time Schedule • March 7, 2004: Submission of final project specification. • March 24, 2004: Submission of first progress report, includes study of the GSM security architecture and the protocols used in the network for security. • April 7, 2004: Submission of second progress report, includes study of various attacks on the protocols. • April 21,2004 : Submission of third progress report, includes possible improvements made to the existing protocols to sustain the attacks and also how to achieve end to end encryption in the network.• April 30,2004 : Submission of final written project report • May 5,2004 : Discussion of the project report and viewgraphs with the instructor • May 7,2004 : Final oral presentation ** The above dates are tentative. We have to discuss with the instructor and fix the dates. List of possible areas, where the specification can change • Based on the progress of the project and the availability of the literature, new attacks on the protocols can be added and existing attacks can be removed from the attack list. References: 1. L.Pesonen, “GSM Interception”, November1999, Proceedings of the Helsinki University of Technology, Seminar on Network Security, http://www.tml.hut.fi/Opinnot/Tik-110.501/1999/papers/gsminterception/netsec.html 2. Michael Street , “Interoperability and international operation of end to end security over mobile networks”, IEE seminar on Secure GSM and Beyond,February 11, 2003,London,UK. http://www.iee.org/OnComms/PN/communications/SecureGSM.cfm 3. Lo, Chi-Chun (Natl Chiao-Tung Univ) Chen, Yu-Jen, “Secure Communication architecture for GSM networks”,IEEE Pacific RIM Conference on Communications,Computers and Signal Processing Proceedings, August 22- August 24,1999. 4. Lo, Chi-Chun (Natl Chiao-Tung Univ) Chen, Yu-Jen, “Secure Communication mechanisms for GSM networks”,IEEE Transactions on Consumer Electronics 45 4 1999 , IEEE p 1074-1080 0098-3063. 5. Al-Tawil, Khalid (King Fahd Univ of Petroleum and Minerals) Akrami, Ali ,Youssef, Habib ,“A New Authentication Protocol for GSM Networks”, IEEE conference on Local Computer Networks,October 11-14 ,1998. 6. Mikko Suominen of the Helsinki University of Technology, “GSM Security” http://keskus.hut.fi/opetus/s38153/k2003/Lectures/g42GSM_security.pdf7. Max Stepanov of Hewbrew University ,Institute of Computer Science, “GSM Security”, http://www.cs.huji.ac.il/~sans/#_Reading_Material 8.Gregory Greenman of Hebrew University ,Institute of Computer Science, “GSM Attacks”, http://www.cs.huji.ac.il/~sans/#_Reading_Material 9. Elad Barkan, Eli Biham, Nathan Keller, “ Instant Ciphertext only Cryptoanalysis of GSM Encrypted Communication”.Proceedings of Crypto May,2003. http://cryptome.org/gsm-crack-bbk.pdf 10. Josyula R. Rao, Pankaj Rohatgi , Helmut Scherzer, Stephane Tinguely, “Partitioning Attacks: Or How to Rapidly Clone Some GSM Cards”,IEEE Symposium on Security and Privacy May