1. Securing AODV Routing Protocol in Mobile Ad-hoc Networks Phung Huu Phu, Myeongjae Yi, and Myung-Kyun Kim Network-based Automation Research Center and School of Computer Engineering and Information Technology University of Ulsan, Ulsan Metropolitan City, 680-749, Republic of Korea Seventh Annual International Working Conference on Active and Programmable Networks November 21-23 2005 CICA, Sophia Antipolis, French Riviera, La Cote d'Azur, FRANCE Network-based Automation Research Center

2. Slide 1 Contents Motivation and Goals The proposed security schema Security analysis Conclusions and future work

3. Slide 2 Motivations The AODV routing protocol is under consideration by IETF for MANET routing protocol standardization Security aspects for AODV also have been studied in other researches Based on unrealistic assumptions about the availability of key management infrastructures => Alternative solutions more suitable to ad hoc networks are needed

4. Slide 3 Goals Consider two related works: ARAN and SAODV These schemas do not consider intermediate nodes during the routing steps nodes may perform fabrication attacks. The goal: design a schema which performs point-to-point message authentication without a deployed key management infrastructure

5. Slide 4 The proposed security schema (1/4) Principle: messages in AODV must be authenticated to guarantee the integrity and non-repudiation Each node maintains table for security info; a record contains: neighbor address, neighbor public key, and a shared secret key The authentication is executed by checking hashed message which is hashed by the shared key

6. Slide 5 The proposed security schema (2/4) Key agreement process 1. Broadcast : 2. For each received message 3. If message_type=AGREEMENT_REQ 4. send 5. ElseIf message_type=AGREEMENT_REP 6. generate a shared key K s ; 7. send 8.ElseIf message_type= KEY_OFFER 9. decrypte to get the shared key K s ; 10.End if; 11. End for; e S and e R are the public key of the sender node and replying node eReR

7. Slide 6 The proposed security schema (3/4) Route request Hased value = hash Ks (RREQ) the hashed value of RREQ message by the shared key K s between the two nodes. IkIk D

8. Slide 7 The proposed security schema (4/4) Route reply and route maintenance Route replies (RREP) in AODV also need to be authenticated; the request and reply for authentication: ; Authentication for route error report message (RERR) ;

9. Slide 8 Security analysis (1/2) The proposed schema is a new fully distributed authentication process does not require any third parties provides the integrity and non-repudiation of messages The schema uses point-to-point authentication process can authenticate intermediate nodes in routing steps does not require a certificate server (like ARAN) or assumption of key distribution (SAODV).

10. Slide 9 Security analysis (2/2) By supplying integrity of exchanging messages, our schema can prevent against attacks A malicious node can not forms loops by spoofing nodesspoofing nodes can prevent falsified error messages or modification attacks during route discovery processfalsified error messages modification attacks However, The end-to-end authentication process has not been considered yet

11. Slide 10 Conclusions A security schema for AODV has been proposed to prevent common kinds of attacks and compensate for the security flaws of recent related works Exchanging messages in AODV are required to be authenticated in point-to-point step by using hash chains during a transaction Shortcomings Some kinds of attacks (tunneling attacks or selfishness problems) have not been considered in this work end-to-end authentication process has not been considered yet

12. Slide 11 Future work The end-to-end authentication procedure will be added to the current approach Trust self-management in the schema will be studied The implementation and simulation of the schema has been investigating on GloMoSim simulation tool

13. Slide 12

14. Impersonate attacks  A malicious node impersonates the source node  A malicious node impersonates the destination node  Forging a RREP with its address as a destination node  Associating with modifying sequence number with a big value  Impersonates the neighbor of destination  A malicious node forms loops by spoofing nodes

15. Modification attacks  Modify hop count field  Reduce the hop count field in RREQ messages The malicious node is included on a newly created route The malicious node is included on a newly created route  Modify destination_seq_# field  after re-broadcasting a RREQ, a malicious node creates a falsified RREQ with increased destination_seq_#

16. Falsifying Route Errors  A malicious node can falsifies a fabrication route error message  A malicious node M spoofs node B and send to node A (previous hop of B in a route to a destination) a error message indicating a broken link between node B and the destination  Node A delete the table entry for the destination and forward the route error message A B S D M Falsified RERR