Securing AODV Routing Protocolin Mobile Ad-hoc Networks

Phung Huu Phu, Myeongjae Yi, and Myung-Kyun Kim

Network-based Automation Research Center andSchool 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 2005CICA, Sophia Antipolis, French Riviera, La Cote d'Azur, FRANCE

Network-based Automation Research Center

Slide 2

Contents

Motivation and Goals

The proposed security schema

Security analysis

Conclusions and future work

Slide 3

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

Slide 4

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

Slide 5

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

Slide 6

The proposed security schema (2/4)

Key agreement process

1. Broadcast : <AGREEMENT_REQ, request_id,sender_addr,eS>

2. For each received message

3. If message_type=AGREEMENT_REQ

4. send <AGREEMENT_REP, request_id, sender_addr, neighbor_addr,eR>

5. ElseIf message_type=AGREEMENT_REP

6. generate a shared key Ks;

7. send <KEY_OFFER, encrypt (Ks)>

8. ElseIf message_type= KEY_OFFER

9. decrypte to get the shared key Ks;

10. End if;

11. End for;

eS and eR are the public key of the sender node and replying node

eR

Slide 7

The proposed security schema (3/4)

Route request

Hased value = hashKs(RREQ) the hashed value of RREQ message by the shared key Ks between the two nodes.

Ik D

Slide 8

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:

• <AUTHEN_RREP_REQ, dest_addr,dest_seq_#>;

• <AUTHEN_RREP_REP, dest_addr, dest_seq_#, hashKs(RREP)>

Authentication for route error report message (RERR)

• <AUTHEN_RERR_REQ,unreachable_dest_addr,

unreachable_dest_seq_#>;

• <AUTHEN_RERR_REP, unreachable_dest_addr,

unreachable_dest_seq_#, hashKs(RERR)>

Slide 9

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).

Slide 10

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 nodes

can prevent falsified error messages or modification attacks

during route discovery process

However,

The end-to-end authentication process has not been considered

yet

Slide 11

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

Slide 12

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

Slide 13

Impersonate attacksImpersonate attacks A malicious node impersonates the source nodeA malicious node impersonates the source node A malicious node impersonates the destination A malicious node impersonates the destination

nodenodeForging a RREP with its address as a destination nodeForging a RREP with its address as a destination nodeAssociating with modifying sequence number with a Associating with modifying sequence number with a

big value big value

Impersonates the neighbor of destinationImpersonates the neighbor of destination A malicious node forms loops by spoofing nodesA malicious node forms loops by spoofing nodes

Modification attacksModification attacks

Modify hop count fieldModify hop count fieldReduce the hop count field in RREQ messagesReduce the hop count field in RREQ messages

The malicious node is included on a newly created The malicious node is included on a newly created routeroute

Modify destination_seq_# fieldModify destination_seq_# fieldafter re-broadcasting a RREQ, a malicious after re-broadcasting a RREQ, a malicious

node creates a falsified RREQ with increased node creates a falsified RREQ with increased destination_seq_# destination_seq_#

Falsifying Route ErrorsFalsifying Route Errors

A malicious node can falsifies a fabrication A malicious node can falsifies a fabrication route error messageroute error messageA malicious node M spoofs node B and send to A malicious node M spoofs node B and send to

node A (previous hop of B in a route to a node A (previous hop of B in a route to a destination) a error message indicating a destination) a error message indicating a broken link between node B and the destinationbroken link between node B and the destination

Node A delete the table entry for the Node A delete the table entry for the destination and forward the route error destination and forward the route error messagemessage

AB

S D

MFalsified RERR