Master Thesis Proposal Evaluation of Routing and Secure routing protocols in Mobile Ad hoc Networks under Network Attacks (or in malicious environment) By Tuan Anh Nguyen School of Science and Computer Engineering University of Houston – Clear Lake 05/2005 Committee members and signatures Approved by: Date: ------------------------------------------------------------Advisor: Dr. T. A. Yang ------------------------------------------------------------Committee member: ------------------------------------------------------------Committee member: Deans ------------------------------------------------------------------------ 1 Table of Contents 1. 2. 3. 4. 5. 6. 7. 8. Abstract ............................................................................................................... 3 Introduction and background ............................................................................. 4 Statement of problem ........................................................................................ 13 Details of the Proposed Investigation ............................................................... 14 Materials and methods of research................................................................... 15 Summary ........................................................................................................... 16 References ......................................................................................................... 16 Appendices ........................................................................................................ 16 2 1. Abstract The nature of wireless ad hoc network makes it very vulnerable to attacks. Most of the attacks target at routing protocols in wireless ad hoc network and most of the security solutions also target at healing the weakness of routing protocols in wireless ad hoc network. Many secure routing protocols are proposed to deal with various kinds of network attacks. But one secure routing protocol can not guarantee the normal operation of the network in every situation. The objective of the thesis is to study the performance of some specific secure routing protocols in various malicious scenarios and to propose an optimal security solution to improve the performance of these secure routing protocols. 3 2. Introduction and background a. Overview of Mobile Ad-hoc NETwork – MANET What is MANET Mobile Ad-hoc NETwork is a set of wireless devices called wireless nodes that dynamically connect and transfer information. Wireless nodes can be personal computer with wireless LAN card, laptop, PDA. In MANET, any wireless node can be the source of data transmission, destination of intermediate node. When a wireless node plays the role of intermediate node, it serves as a router that can receive and forward data packets to its neighbor closer to the destination node. Due to the nature of an ad-hoc network, the network topology changes from time to time. A node is serving the role of router may be get out of the route between source and destination then the route is disconnected and route discovery process has to be restarted. Thus the main goal of routing protocol in MANET is to find a correct route efficiently. MANET has various potential applications. Some typical examples include emergency search-rescue operations, meeting events, battle field communication between moving vehicles. With the ability to meet the demand of mobile computation, army application.., MANET has a very bright future. Picture 2.1 Overview of Mobile Ad-hoc Network b. Routing protocols in MANETs Routing protocols in ad hoc mobile wireless network can generally be divided into 2 groups [5]: - Table driven: every node in the network maintains complete routing information about the network by periodically propagating the updates. Thus when a node needs to send packet, there is no delay for searching the route throughout the network. This kink of routing protocols roughly works the same way as that of routing protocols for wired networks. - Source initiated (or demand driven): Node just maintains routes to active destinations that it needs to send data. The routes to active destinations will expire after sometime of not be used or node does have data to send. 4 Ad hoc routing protocols Table-driven DSDV Source-initiated on-demand WRP AODV DSR Picture 2.2 Hierarchy of routing protocols Here we describe the overview of some of the most common routing protocols used in mobile ad hoc network - Table-driven routing protocols i. Destination Sequence Distance Vector Routing – DSDV DSDV protocol a distance vector routing protocol is based on Bellman-Ford algorithm. The Distance Vector algorithm has drawbacks as routing loop and counting to infinity. However, improvements have been made to Bellman-Ford to ensure loop-free routing table. Every node in the network maintains a routing table that contains routes to all other nodes with metrics as hop counts. Each entry in the routing table also includes sequence number assigned by the destination. This sequence number allows node to differentiate new routes from the old ones. Routing table is periodically broadcasted to other nodes to maintain the consistency of routing tables throughout the network. Routing table is transmitted throughout the network by two ways. First is full table transmission and the second is incremental update what is changed since the last full table transmission. Routes that resulted an improved metric are scheduled for a broadcast at a later time. The time depends on the average settling time for routes to the particular destination. Some times there could be a burst of advertisement packets in rapidly changing environments. The Mobile host delays the advertisement of such routes to avoid the bursty behavior. It keeps a history of weighted average time that routes to particular destination fluctuate until the route with the best metric is received. 5 When node first exists in the network, it sends out a broadcast message with its locally maintained sequence number. The odd sequence numbers are for infinity distance while even numbers are for normal operation. Node periodically sends out beacon message to announce its existence. Neighbors receive the message and compare with what they have in routing table. If the sequence number is bigger of equal and metric is better then neighbors will update their table with the information contained within the message. The new information is scheduled to broadcast further and the metric is incremented by one hop. The information can be advertised when asked for of there is a major change in the network topology. That’s why protocol is considered as both table-driven and timedriven. Nodes delay the advertisement of the new route, thus they maintain two tables; one is for forwarding packets and the second one to advertise the routes. When no broadcast packets are received from the neighbors then the link is considered to be broken. Any route through that next hope is immediately assigned infinity metric and assigned an updated sequence number. The sequence numbers generated to indicate infinite metrics are odd numbers. ii. Dynamic Source Routing - DSR c. Security goals in MANETs To secure an ad hoc environment, researchers consider the following parameters: availability, confidentiality, integrity, authentication and non-repudiation. Availability guarantees the survivability of network services despite of service attacks. A Denial-of-Service (DoS) is a potential threat at any layer of an ad hoc network. On the media access control layer an adversary could jam the physical communication channels. On the network layer disruption of the routing operation may result in a partition of the network, rendering certain nodes inaccessible. On higher levels an attacker could bring down high-level services like key management service. 6 Confidentiality ensures that certain information be never disclosed to unauthorized entities. It is of paramount importance to strategic or tactical military communications. Routing information must also remain confidential in some cases, because the information might be valuable for enemies to locate their targets in battlefield. Integrity ensures that a message that is on the way to destination is never corrupted. A message could be corrupted because of channel noise or because of malicious attacks on the network. Authentication enables a node to ensure the identity of the peer node. Without authentication, an attacker could masquerade a node, thus gaining access to sensitive information. Non-repudiation ensures that the originator of a message cannot deny that it is the real originator. Non-repudiation is important for detection and isolation of compromised nodes. Authorization is important for a node to be sure that the node it gives authority is not an attacker or a compromised node. d. Secure routing protocols Describe the nature of ad hoc network, the weakness of nodes, and the weakness of routing protocol. The weakness of node mostly is the technical drawback in materials and production. Hardware technology improves very fast so it limits the effectives based on hardware limitation. But the situation is not the same with routing protocol. The weakness in routing protocols stays the same if we don’t do anything to improve it. There are various solutions to heal the weakness of routing protocols. i. Secure Efficient Ad-hoc Distance vector routing protocol - SEAD (improved DSDV) 7 SEAD is based on the design of Destination-Sequenced Distance-Vector (DSDV) routing protocol. This routing protocol serves the network with limited power nodes and helps to protect against Denial of Service attacks that cause the nodes to exceedingly consume network bandwidth and processing time. SEAD achieves this purpose by using efficient one-way hash functions. Hu, Perrig and Johnson introduced a table-driven routing protocol based on the DSDV algorithm [5]. In a table driven routing protocol nodes periodically exchange routing information with other nodes. SEAD is built on top of the DSDV-SQ version of the DSDV protocol that outperforms the basic DSDV. SEAD deals with modification attacks that try to change the routing information during the update phase of DSDV-SQ protocol. More specifically routing can be disrupted if the attacker modifies the sequence number and the metric field of the routing table entry. In SEAD replay attacks are also taken into account as a security threat. To secure the DSDV-SQ protocol, SEAD uses efficient one way hash chains rather than counting on expensive asymmetric cryptography operations. SEAD assumes some mechanism for a node to distribute an authentic element of the hash chain. Authors suggest ensuring the key distribution relying on a trusted entity that signs public key certificates for each node. Then each node can use its public key to sign hash chain element and distribute it. The basic idea behind SEAD is to authenticate the sequence number and metric pair of a routing table update message using hash chain elements. The receiver of SEAD routing information also authenticates the sender, ensuring that the routing information originates from the correct node. To create a one-way hash chain, a node chooses an initial random value “x” to form the hash chain: h0, h1, … , hn where h0=x and hi=H(hi-1) for 0<i<n for some n. A Hash function takes an input and maps it to a p-bit length output. It is easy to compute a hash function but infeasible to invert it back. H:{0,1}*→{0,1} 8 p For example, given an authenticated hi value it is possible to authenticate hi-3 by H( H ( H (hi-3) ) ) which should be equal to hi. Each node uses a specific authentic element from its hash chain in each routing update that it sends about itself (metric 0). Based on this initial element, the one-way hash chain provides authentication for the lower bound on the metric in other routing updates for that node. The use of a hash value corresponding to the sequence number and metric in a routing update entry prevents any node from advertising a route to some destination claiming a greater sequence number than that destination’s own current sequence number. Likewise, a node cannot advertise a route better than those for which it has received an advertisement, since the metric in an existing route cannot be decreased due to the oneway nature of the hash chain. When a node receives a routing update, it checks the authenticity of the information for each entry in the update using the destination address, the sequence number and the metric of the received entry, together with the latest prior authentic hash value received from that destination’s hash chain. Hashing the received elements the correct number of times (according to the prior authentic hash value) assures the authenticity of the received information if the calculated hash value and the authentic hash value match. The source of each routing update message in SEAD must also be authenticated, since otherwise, an attacker may be able to create routing loops through the impersonation attack. ii. ARIADNE (improved DSR) A second proposal by Hu, Perrig and Johnson presents an on-demand ad hoc routing protocol based on DSR, ARIADNE [4]. ARIADNE withstands node compromise and relies only on highly efficient symmetric cryptography. It also guarantees that the destination node of a route discovery process can authenticate the originator. The originator can authenticate each intermediate node on the path to the destination present in the RREP message and can ensure that no intermediate node can remove a previous node in the node list in the RREQ or RREP messages. ARIADNE needs a mechanism to enable each node to share a secret key (i.e., KSD between source and destination). A TESLA key for each node in the network and an 9 authentic “Route Discovery Chain” element for each node for which this node will forward RREQ messages must be securely known. ARIADNE provides a point-to-point authentication of a routing message using a Message Authentication Code (MAC) and a shared key between the two entities. For authentication of RREQ packets, ARIADNE uses the TESLA broadcast authentication protocol. ARIADNE copes with attacks performed by malicious nodes that modify and fabricate routing information. In ARIADNE, the basic RREQ mechanism is enriched with eight fields used to provide authentication and integrity to the routing protocol. <ROUTE REQUEST, initiator, target, id, time interval, hash chain, node list, MAC list>. The initiator and target are the address of source and destination nodes respectively. Like DSR, the initiator sets the id to an identifier that it has not recently been used in initiating a Route Discovery. The time interval is a TESLA related parameter that is the pessimistic expected arrival time of the request at the target, accounting for clock skew. The initiator of the request then initializes the hash chain to MACKSD (initiator, target, ID, time interval) and the node list and MAC list to empty lists. When a node A receives a RREQ for which it is not the target, the node checks its local table of <initiator, id> values from recent requests it has received, to determine if it has already seen a request from this same Route Discovery. If it has, the node discards the packet, as in DSR. The node also checks whether the time interval in the request is valid: that time interval must not be too far in the future, and the key corresponding to it must not have been disclosed yet. If the time interval is not valid, the node discards the packet. Otherwise, the node modifies the request by appending its own address (A) to the node list in the request, replacing the hash chain field with H [A, hash chain], and appending a MAC of the entire REQUEST to the MAC list. The node uses the TESLA key K Ai to compute the MAC, where i is the index for the time interval specified in the request. Finally, the node rebroadcasts the modified RREQ, as in DSR. When the target node 10 receives the RREQ, it checks the validity of the request by determining that the keys from the time interval specified have not been disclosed yet, and that the hash chain field is equal to: H [hn , H [hn-1 , H [ . . . , H [h1 , MACKSD (initiator, target, id, time interval) ]..] ] ] where hi is the node address at position i of the node list in the request, and where n is the number of nodes in the node list. If the target node determines that the request is valid, it returns a RREP to the initiator, containing eight fields: <ROUTE REPLY, target, initiator, time interval, node list, MAC list, target MAC, key list>. Figure – ARIADNE route discovery The target, initiator, time interval, node list, and MAC list fields are set to the corresponding values from the RREQ, the target MAC is set to a MAC computed on the preceding fields in the reply with the key KDS, and the key list is initialized to the empty list. The RREP is then returned to the initiator of the request along the source route obtained by reversing the sequence of hops in the node list of the request. An intermediate node that forwards the RREP waits till it is able to disclose its key from the time interval specified. Afterwards it appends its key from that time interval to the key list field in the reply and forwards the packet according to the source route indicated in the packet. When the originator receives a RREP, it verifies that each key in the list is valid, that the target MAC is valid, and that each MAC in the MAC list is valid. After the success of this tests the node accepts the RREP. In order to avoid the injection of invalid route errors into the network by any node other than the one on the sending end of the link specified in the error message, each node that encounters a broken link adds TESLA authentication information to the error message. On the other hand TESLA authentication is delayed, so all the nodes on the return path buffer the error but do not consider it until it is authenticated. Later, the node that saw the 11 broken link discloses the key and sends it over the return path, which enables nodes on that path to authenticate the buffered error message. ARIADNE is secure against the wormhole attacks only in its advanced version that uses the TIK (TESLA with Instant Key disclosure) protocol that allows for very accurate time synchronization between the nodes of the network. It can also detect anomalies in routing traffic flows in the network. e. Attacks on Wireless Ad-hoc Network Attack in wireless as attack to network in general can be divided into 2 groups – passive and active. With passive attacks, the attacker just collect the information from the data transmission over the network without causing any damage to network while active attackers try to disrupt the normal operation of nodes in the network or try to damage data or even try to bring the whole network down. The purpose of passive attacks is military, commercial or just for curiosity. The purpose of the active attack is also military, commercial sometime just practical pranks to show off the technical ability. Especially, a node with technical problem can be considered an attacker though it indeliberately disrupts data transmission. Here we don’t go into details of purpose of the attacks. We just focus on technical aspects. i. Passive attacks: This kind of attack targets at collecting valuable information from the network. The information includes the data transferred, the identification of communicating nodes, net work topology and more. ii. Active Attacks 1. Power consumption attack Mostly based on DOS attack. 2. Routing attacks - Malicious node introduce false information, confuses the routing procedure. By doing that, it can degrades the performance of the network. - Malicious node claims that it has the best path to a destination then it attracts all traffics and discards the traffic. - Malicious node can request for non-exist address and causes the network flooded by these RREQs. These RREQs consume the bandwidth and degrade the performance. Denial Of Service – DOS 2 typical kinds of DOS attacks are radio jamming and battery exhaustion [4] Impersonation Fabrication Blackhole Wormhole 12 3. Statement of problem The mobile ad hoc network is a new model of wireless communication and increasingly gains attention from industry. As in general networking environment, mobile ad-hoc net works have to deal with various security threats. Due to the nature of dynamic network topology, routing in mobile ad-hoc network play a vital role for the performance of the networks. It is understandable that most of security threats target at routing protocols – the weakest point of mobile ad-hoc network. There are various study and research in this field in attempt to propose more secure protocols. However, there is not a complete routing protocol that can entirely secure the operation of one network in every situation. A secure protocol can protect the network against one specific type of attack but can not protect for other kinds. Many researches have been done to evaluate the performance of secure routing protocols in comparison with normal routing protocols. The purpose of these researches is to discover the additional cost of adding security feature into non-secure routing protocols in various scenarios. The additional cost includes delay in packet transmission, the low rate of data packets over the total packets sent and many more factors. However, in the real world, there are no ideal working environments. There are always threats and malicious actions affecting the performance of mobile ad-hoc network. Thus studying the performance of secure routing protocols in malicious environments is a need in order to exhaustively evaluate the performance of these routing protocols. In the thesis I will implement 2 secure routing protocol: secure efficient distance vector routing SEAD and a secure on demand routing protocol ARIADNE in OPNET simulation environment. I also create malicious scenarios in OPNET by implementing several attacking scenarios. 13 By implementing secure routing protocols and running these routing protocols in malicious environments, I hope that I will discover the weaknesses of these secure routing and propose a solution to heal the weaknesses or to improve the performance of these secure routing protocols. 4. Details of the Proposed Investigation One of method to conduct the research in this field is to simulate the performance of these secure routing protocols. Fortunately, there are various computer simulation software that help doing this kink of research such as NS-2, OPNET, Glomosim .. In this thesis, I will implement 2 secure routing protocols SEAD and ARIADNE in OPNET simulation environment. I will run standard routing protocols – AODV and DSDV (already built-in protocols in OPNET simulation) to create the base line performance then I will run secure versions of these routing to compare the performance against the base lines. The next step I will run these secure routing protocols in malicious environments and compare with their performance in previous step in order to unveil the weaknesses of these routing protocols. Based on performance analysis of these secure routing protocols, I will propose a solution to improve the performance of these routing protocols. Time table - Implement secure routing protocols such as SEAD and ARIADNE in OPNET simulation environment. - Running routing and secure routing protocols in benign environments to get baseline performance. 14 - Running secure routing protocols in various malicious scenarios. - Study the affects of scenarios in the performance of secure routing protocols - Propose a solution to routing protocols to get better performance. 5. Materials and methods of research The thesis is heavily based on the implementation and experiment in a simulation environment. OPNET is chosen as a simulation environment. Specifically, OPNET developer will be exploited to create experiment scenarios. OPNET has several already implemented routing protocols such as AODV, DSDV, DSR, TORA but nothing for secure routing protocols. Security routing protocols SEAD and ARIADNE will be implemented using Application Programming Interface of OPNET development kit and C language embedded in it. a. Experiments b. Experimental Environment i. NS-2 ii. OPNET c. Environment Setup d. Proposed Schedule: Study simulation tool and environment Implement routing protocols for research. Implement and simulate the attacks Analyze the results Conclusion Report and defend. 15 6. Summary 7. References [1] On Vulnerability and protection of Ad hoc On Demand Distance Vector Protocol Weichao Wang, Yi L, Bharat Bhargava – Purdue University [2] Steal Attack on Adhoc Wireless Networks Mrkus Jakobsson, Susanne Wetzel and Bulent Yener [3] Security in Ad-hoc Routing Protocols Frederic Martin, Houy-Sy Thao, Magnus Thylander – National University of Singapore [4] Security in wireless ad-hoc networks – The handbook of Ad hoc wireless network Amitabh Mishra, Ketan M. Nadkarni – Virginia polytechnic Institute and State University. [5] A review of current routing protocols for ad hoc mobile wireless networks Elizabeth M. Royer – University of California Santa Barbara Chai-Keong Toh – Georgia Institute of Technology [6] SEAD secure efficient distance vector routing for mobile wireless ad hoc networks Yih-Chun Hu, David B.Johnson, Adrian Perrig. – Carnegie Mellon University and Rice University Houston. 8. Appendices Byzantine: 16