Sensor networks [5][6][7][9] are highly distributed networks of
small, lightweight wireless nodes, deployed in large numbers to
monitor the environment or system by the measurement of
physical parameters such as temperature, pressure, or relative
humidity. Building sensors have been made possible by the
recent advances in micro-electromechanical systems (MEMS)
technology. The sensor nodes are similar to that of a computer
with a processing unit, limited computational power, limited
memory, sensors, a communication device and a power source in
form of a battery. In a typical application, a WSN is scattered in
a region where it is meant to collect data through its sensor
nodes. The applications of sensor networks are endless, limited
only by the human imagination [5] [6] [7]. In this paper an
overview on various WSN attacks are mentioned with a special
mention on Denial of Service (DoS). Summery on the
counterattacks and possible preventive measures are mentioned.
It is to be mentioned that all the attacks are mentioned
thoroughly as well as the preventive measures mentioned in this
paper is also not exhaustive. The rest of the paper is as follows:
Section 2 gives an overview on the applications of WSN followed
by section 3 in which various types of attacks on WSN are
highlighted. In section 4 countermeasures of the WSN security
threats are discussed by the conclusion in section 5