Security Threats and Issues with MANET

Security Threats and Issues with MANET

Sudha Singh (Bengal College of Engineering and Technology, India)
DOI: 10.4018/978-1-4666-0321-9.ch015


In recent years, mobile ad hoc networks have received tremendous attention because of their self configuration capabilities. Although security has long been an active research topic in wireless networks, the unique characteristics of MANETs present a new set of non trivial challenges to security design. These challenges include open network architecture, shared wireless medium, stringent resource constraints, and highly dynamic network topology. Consequently, the existing security solutions for wired networks do not directly apply to the MANET domain. The ultimate goal of the security solution for MANET is to provide security services, such as authentication, confidentiality, integrity, anonymity, and availability to the mobile users. One distinguishing characteristics of MANETs from the security design perspective is the lack of a clear line of defense. The wireless channel is accessible to both legitimate network users and malicious attackers. There is no well defined place where traffic monitoring or access control mechanisms can be deployed. As a result, the boundary that separates the inside network from the outside world becomes blurred.
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I. Introduction

The research on MANET security is still in its early stage. The existing proposals are typically attack-oriented in that they first identify several security threats and then enhance the existing protocol or propose a new protocol to thwart such threats. Because the solutions are designed explicitly with certain attack models in mind, they work well in the presence of designated attacks but may collapse under unanticipated attacks. Therefore, a more ambitious goal for ad hoc network security is to develop a multi-fence security solution that is embedded into possibly every component in the network, resulting in in-depth protection that offers multiple lines of defense against many both known and unknown security threats.

A MANET is an autonomous collection of mobile users that communicate over relatively bandwidth constrained wireless links. Since the nodes are mobile, the network topology may change rapidly and unpredictably over time. The network is decentralized, where all network activity including discovering the topology and delivering messages must be executed by the nodes themselves, i.e., routing functionality will be incorporated into mobile nodes. Anonymity is another important issue. A MANET environment is vulnerable to eavesdropping, where an adversary can track and analyze the traffic flow through a network, and identify or locate a certain sender/receiver, even if it cannot crack the encrypted data (Cordasco and Wetzel,2009).

Ad hoc have several salient characteristics(Toh,2007; Ilyas,2003): (1) Distributed Operation: The ad-hoc concept differs from other wireless systems, such as cellular system in terms of network operation. An ad-hoc network comprises stations that have the same capabilities and responsibilities. No centralized entry that controls the network exists. In an ad-hoc network there are no BSS or MSCs thus all network protocols operate in a distributed manner. (2) Dynamic topologies: Nodes are free to move arbitrary, thus the network topology which is typically multihop may change randomly and rapidly at unpredictable times, and may consist of both bi-directional and unidirectional links. (3) Bandwidth-constrained, variable capacity links: Wireless links will continue to have significantly lower capacity than their hardwired counterparts. In addition, the realized throughput of wireless communication after accounting for the effects of multiple access, fading, noise and interference condition, etc. is often less than a radios maximum transmission rate. One effect of the relatively low moderate link capacities is that congestion is typically the norm rather than the exception i.e. often much less than a radios maximum transmission rate. (4) Energy constrained operation: Some or all of the nodes in a MANET is a may rely on batteries or other exhaustible means for their energy. For these nodes, the most important system design criteria for optimizing may be energy conservation. (5) Multihop communication: In case where a station A needs to send data to another station B out of range, the transmission needs to relayed through other nodes. Such networks are known as multihop wireless ad-hoc network. Example: HIPERLAN,WLAN.(6) Limited physical security: mobile networks than fixed networks (wired and wireless) are more vulnerable to security threats. Need to overcome the security weaknesses in wireless links and mobile topologies arising from the new security risks.

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