1 Rushing Attacks and Defense in Wireless Ad Hoc Network Routing Protocols Yih-Chun Hu, Adrian Perrig, and David B. Johnson Presented By: Nitin Subramanian (Slides Courtesy: Sandeep Mapakshi CS 6910-ACIS – Project 6 Instructor: Prof. Leszek T. Lilien, Fall 2006 Department of Computer Science Western Michigan University)

2 Outline On-Demand Routing Protocols Rushing Attacks Rushing Attack Prevention Evaluation Conclusion

3 On-Demand Route Discovery A A A-B A-C A-C-E A-B-DA-B-D-G B G D E C A F H source Destination

4 The Rushing Attack On-demand routing protocols use duplicate suppression at each node: first ROUTE REQUEST that reaches a node is considered legitimate, next are discarded (all have the same identifier, higher identifiers denote new requests) Attacker scatters RREQ quickly throughout the network suppressing any later legitimate RREQ Initiator will be unable to discover any usable routes containing at least two hops An effective denial-of-service attack

5 Why is the Attack Possible? An attacker can send faster, by avoiding the delays that are part of the design of both routing and MAC (802.11b) protocols. Why Delay in ROUTE REQUEST forwarding ? In a MAC protocols using time division On-demand protocols generally specify a delay Remove these delays at both the MAC and routing layers? - more collisions Attacker can send at a higher wireless transmission level An attacker can take advantage of a wormhole, to create flood rushing attacks, use the wormhole to rush the packets ahead of the normal flow

6 Rushing Attack S D Slide courtesy: [2]

7 Rushing Attack Example ●A sends a ROUTE REQUEST

8 Rushing Attack Example ●A sends a ROUTE REQUEST ●B forwards the REQUEST without checking the signature, or otherwise rushes the REQUEST

9 Rushing Attack Example ●A sends a ROUTE REQUEST ●B forwards the REQUEST without checking the signature, or otherwise rushes the REQUEST ●C correctly processes the REQUEST, and forwards it later as a result

10 Rushing Attack Example ●A sends a ROUTE REQUEST ●B forwards the REQUEST without checking the signature, or otherwise rushes the REQUEST ●C correctly processes the REQUEST, and forwards it later as a result ●Since D has already heard a REQUEST from this discovery, D discards the REQUEST

11 Rushing Attack Example ●B rushes the REQUEST ●C forwards it later ●Since D has already heard a REQUEST from this discovery, D discards the REQUEST ●A discovers a path through B because B rushed the REQUEST

12 Rushing Attack Example Route discovery process under no attack B E D C A Route Query Route Reply

13 Rushing Attack Example Route discovery process under attack B E D C A Route Query Route Reply Attacker

14 Wormhole Attack Attacker records a packet at one location in the network, tunnels the packet to another location. Packets may be replayed from the far end of the wormhole. Puts attacker in a powerful position. It’s a replay so authentication does not help Applications of the Wormhole Attack Denial-of-Service Routing Disruptions Unauthorized Access

15 Routing Tree Adapted from Chris Karlof and David Wagner's WSNPA slides

16 Routing Adapted from Chris Karlof and David Wagner's WSNPA slides

17 Wormhole Attack Tunnel packets received in one place of the network and replay them in another place The attacker can have no key material. All it requires is two transceivers and one high quality out-of-band channel Adapted from Chris Karlof and David Wagner's WSNPA slides

18 Disrupted Routing Most packets will be routed to the wormhole The wormhole can drop packets or selectively forward packets to avoid detection Adapted from Chris Karlof and David Wagner's WSNPA slides

19 What Protocol s Are Vulnerable? On-demand unsecure (AODV, DSR) and secure (ARAN, Ariadne, etc) protocols Result: when under attack, the routing protocol will not be able to discover paths longer than 2 hops

20 Network Assumption Network links are bidirectional Ignore unidirectional links Ignore jamming attack Requires additional hardware Easier to detect Disregard attacks on MAC protocol MAC (Medium Access Control) ALOHA and Slotted ALOHA Medium-sized 50 ～ 500 nodes Clustering

21 Security Assumptions And Key Setup Fast authentication protocol Instantly-verifiable broadcast authentication Keys setup Broadcast authentication key are distributed in advance Powerful attacker Coordinated attacker

22 Secure Routing Requirements And Protocol Secure Neighbor Detection Secure route delegation Randomized ROUTE REQUEST forwarding Single-Hop? Gather n REQUESTS; Randomly Choose 1 Secure Neighbor Detection Original Routing Protocol yes no

23 Secure Neighbor Detection Neighbor Detection Two nodes detect a bidirectional link between themselves In Proactive routing protocol In Reactive routing protocol Requirements Sender-receiver can check that the other is within the normal communication range Node needs to hear Neighbor Request

24 Secure Neighbor Detection Three-round mutual authentication protocol S broadcasts a Neighbor Request packet R return a Neighbor Reply packet to S S sends a Neighbor Verification to B Short delay timing Within a maximum communication range neighbor Request broadcast neighbor reply senderreceiver neighbor verfication

25 Notation

26 Secure Neighbor Detection (cont.) Nonces η 1, η 2 freshness S R1R1 R2R2

27 Secure Neighbor Detection (cont.) Integration with an On-Demand Protocol A  ＊ :REQUEST || Neighbor Request A B  A:Neighbor Reply B  A || Neighbor Request B A  B:Neighbor Verification A  B || Neighbor Reply A  B B  ＊ :REQUEST || Neighbor Verification A  B || Neighbor Verification B  A

28 Secure Route Delegation Delegate neighbor to forward the Route Request packet To verify that both nodes of each adjacent node pair indeed believes to be a neighbor A received ROUTE REQUEST S  R || id M A = Σ M A =Sign(H(M A )) A  B:

29 Randomized Message Forwarding To minimize the chance that a rushing adversary can dominate all returned routes Randomized message forwarding Collects a number of REQUESTs Selects a REQUEST at random to forward The number of REQUEST packets collected The more the better? The algorithm by which timeouts are chosen Topology closer Geographically closer Randomly

30 Secure Route Discovery To secure any protocol using an on-demand Route Discovery protocol Secure Neighbor Detection Secure route delegation Randomized ROUTE REQUEST forwarding To limit the number of REQUESTs that traverse an attacker The nodes that don’t have n distinct path to the source of the REQUEST Choose a random timeout Two addition security optimizations Each REQUEST signed Use location information

31 Evaluation Simulation Evaluation Underlying protocol: Adriane HORS as broadcast signature 100 nodes 1000 m x 1000 m Random waypoint model Pause Time: 0, 30, 60, 120, 300, 600, 900 Workload: 5 flows 4 packets per second 64-byte packets

32 Overall Evaluation RAP adds significant costs Higher costs due to congestion at lower bit rates. RAP is designed to be used only when necessary Only when underlying protocol is unable to discover a working route Security Analysis Attacker needs to propagate ROUTE REQUEST from each ROUTE DISCOVERY from many locations. Wouldn’t do it if they considered due to intrusion detection

33 Conclusion Described the Rushing attack Presented RAP (Rushing Attack Prevention) RAP incurs higher overhead, but it can find usable routes when other protocols cannot work

34 [Backup Slides] Packet Delivery Ratio % of Offered traffic DSR 99.8% to 100% Ariadne 95% to 100% RAP 7.6% to 47.7% MAC-layer congestion Slide courtesy: [2]

35 [Backup Slides] Median Latency DSR and Ariadne zero mean latency RAP Congestion Waiting to forward a REQUEST Slide courtesy: [2]

36 [Backup Slides] Packet Overhead 5 flows has 5x as much overhead Reduces usefulness Overhead should reduce when congestion not an issue Slide courtesy: [2]

37 [Backup Slides] Introduction Wireless Ad hoc network a collection of mobile computers (or nodes) cooperate to forward packets dynamic topology self-organization

38 [Backup Slides] Introduction (cont.) Routing protocol Transport Subsystem Neighbor State Maintenance Database Maintenance Ad hoc network routing protocols Run in untrusted environments Provide resilience against misconfigured nodes

39 [Backup Slides] Routing Protocols Proactive routing protocol Table-Driven routing protocol Reactive routing protocol Source-Initiated On-Demand routing protocol Forward ROUTE REQUEST packets when needed

40 [Backup Slides] Comparison between Table-Driven Routing and On-Demand Routing Table-driven Routing On-demand Routing Availability of Routing information Immediately from Route Table After Route discovery Route updates Periodic advertisements When requested Routing overhead Proportional to size of network regardless of network traffic Proportional to number of communication nodes and increase with increased node mobility

41 References [1] Yih-Chun Hu,Adrian Perrig, David B.Johnson, “Rushing attacks and defense in wireless ad hoc network routing protocols”, Proceedings of the 2003 ACM workshop on Wireless security, San Diego, CA, USA. Available at: routing/wise2003.pdfhttp:// routing/wise2003.pdf [2] Rushing Attacks and Defense in Wireless Ad Hoc Network Routing Protocols Yih-Chun Hu, Adrian Perrig, and David B. Johnson Presenter: Tammy Nguyen. Available at: