Wireless Sensor Networks (WSN) are up-and-coming as both an important new tier in the IT bionetwork and a rich domain of active research involving hardware and system plan, networking, distributed algorithms, programming models, data management, security and social factors [Culler, D. E and Hong, W.], [Dai, S, Jing, X, and Li, L]. WSN is particularly susceptible against external and internal attacks due to its exacting characteristics. It is necessary to provide WSN with basic security mechanisms and protocols that can guarantee a negligible protection to the services and the in order flow. This means the hardware layer needs to be protected against node cooperation, the communication channels should meet certain security goals (like privacy, honesty and authentication), and the protocols and services of the network must be robust next to any possible interference. A Wireless Sensor Network (WSN) can be definite as a group of sovereign nodes, communicating wirelessly over limited frequency and bandwidth [Akyildiz, I. F, and Su, W., Sankarasubramaniam, Y. and Cayirci, E]. Distributed sensing allows for closer placement to the phenomena to be achieved, when the exact location of a particular event is unknown, than is possible using a single sensor [Bharathidasan, A., Anand, V., Ponduru, S.].

Wireless Sensor Networks are susceptible to security attacks due to the transmit nature of the transmission medium. Basically attacks are broadly confidential in two categories i.e. active attacks and passive attacks. This paper points out both of these attacks in details.

PASSIVE ASSAULT

To keep an eye on the statement channel by illegal assaulters are known as passive attack. Some of the more ordinary attacks against sensor privacy are:

This is the most common attack to privacy. By inquisitive to the data, the adversary could easily find out the communication contents.

Even when the messages transferred are encrypted, it still leaves a high option analysis of the communication patterns. Sensor activities can potentially reveal enough information to enable an adversary to cause malicious harm to the sensor network.

One can insert their node or cooperation the nodes to hide in the sensor network. After that these nodes can copy as a normal node to attract the packets, then misroute the packets, conducting the privacy analysis.

The unauthorized attackers monitors, listens to and modifies the data stream in the communication channel are known as active attack. The following attacks are active in nature.

2

In a sense or network, sensors monitor the changes of precise parameters or values and report to the sink according to the requirement. While sending the report, the information in transit may be altered, spoofed, replayed again or vanished. As wireless statement is susceptible to eavesdropping, any attacker can monitor the traffic flow and get into action to break off, intercept, modify or fabricate packets thus, give wrong information to the base stations or sinks.

A malicious node can selectively drop only certain packets. Particularly effective if combined with an attack that gathers much traffic via the node. In sensor networks it is unspecified that nodes devotedly forward received messages. But some compromised node might refuse to forward packets, however neighbors might start using another route.

In this attack, a malicious node acts as a black hole to pull towards you all the traffic in the sensor network. In fact, this attack can affect even the nodes those are considerably far from the base stations.

[1] Akyildiz, I. F., Su, W., Sankarasubramaniam, Y., Cayirci, E. (2002) ‘A Survey on Sensor Networks’, IEEE Communications Magazine, 40(8), 102-114. [2] Bharathidasan, A., Anand, V., Ponduru, S. (2001), Sensor Networks: An Overview, Department of Computer Science, University of California, Davis 2001. Technical Report. [3] David Boyle, Thomas Newe “Securing Wireless Sensor Networks: Security Architectures” journal of networks, vol. 3, no. 1, january 2008. [4] Vikash Kumar, Anshu Jain and P N Barwal “Wireless Sensor Networks: Security Issues, Challenges and Solutions” International [5] Culler, D. E and Hong, W., “Wireless Sensor Networks”, Communication of the ACM, Vol. 47, No. 6, June 2004, pp. 30-33. [6] Dai, S, Jing, X, and Li, L, “Research and analysis on routing protocols for wireless sensor networks”, Proc. International Conference on Communications, Circuits and Systems, Volume 1, 27-30 May, 2005, pp. 407-411. [7] Al-Sakib Khan Pathan, Hyung-Woo Lee, Choong Seon Hong “Security in Wireless Sensor Networks: Issues and Challenges” ICACT2006, ISBN 89-5519-129-4