International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 05 Issue: 02 | Feb-2018 www.irjet.net p-ISSN: 2395-0072 © 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 377 A Critical Analysis on Network Layer Attacks in Wireless Sensor Network Swathi B.H. 1 , Gururaj H.L. 2 1 M.Tech, Dept. of Computer Science and Engineering, Vidyavardhaka College of Engg., Karnataka, India 2 Assistant Professor, Dept. of Computer Science and Engineering, Vidyavardhaka College of Engg, Karnataka, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - There are several arriving trends in the field of networks, among those Wireless Sensor Networks(WSNs) are gaining importance recent years due to its impact on cost, ability to cope up with node and communication failure, capability to withstand harsh environmental condition, mobility and ease of use. WSNs have widespread applications in the areas of medicine, environment monitoring, military, battlefield awareness, home application management etc. WSNs performs information gathering and processing in real time. In general, these networks are deployed in hostile and remote environment. Hence they are vulnerable to various security threats that adversely affect performance. The information in sensor network needs to be protected against various attacks. Attackers may employ various security threats making the WSN system vulnerable and unstable. A detailed analysis of Network Layer attacks are done. A comparative study of the attacks are made based on the vulnerability, nature of attacks and security services. Key Words: Wireless Sensor Network, Sybil, Wormhole, Sinkhole, Selective Forwarding, HELLO flood, Black hole 1. INTRODUCTION Wireless Sensor Networks(WSNs) have been an active research field over the last decade[1].Wireless Sensor Networks are generally formed by number of small sensor nodes and each node is capability of sensing and forwarding data. Each node is a combination of several components such as transceiver, microcontroller, memory , sender and receiver, power supply and sensor along with digital to analog converter (A/D Converter).The architecture of a sensor node is depicted in Fig- 1. Fig-1 General architecture of sensor node Sensor nodes gather the information from surrounding environment like sound, humidity, light, pressure, vibration, velocity, temperature and magnetism. When these sensor nodes are implemented in systematic way, these sensors organize themselves automatically and built a dedicated ad- hoc multi hop network and each node can communicate with other node within this network. At the sink, user remotely gives command to nodes via the wireless network and collect data after processing stored into a storage device. These nodes also receive the sensed data from the sink nodes. Wireless sensor networks involved in certain applications like area monitoring, agriculture monitoring, earth sensing such as air pollution monitoring and fire detection, water quality monitoring, home appliance management ,industrial monitoring like data logging and data centre monitoring, Habitat monitoring and medical care etc[2]. Some application of the wireless sensor networks are shown in Fig-2. Fig-2 Wireless Sensor Networks Application