Survey on different attacks in Wireless Sensor Networks and their prevention system

---------------------------------------------------------------------***--------------------------------------------------------------------Abstract – Wireless Sensor Network (WSN) is a large network of sensor nodes. Wireless Sensor Networks are very popular and have their special characteristics such as limited battery, limited power and limited storage that makes the energy consumption. Although there are some limitations but there are many advantages of Wireless Sensor Networks. Some advantages are robustness, scalability, flexibility. WSN also reduces the cabling cost. Now a days WSN is mostly used in modern technologies to gain the output in most efficient way. Some applications of WSN are area monitoring, health care monitoring, Earth sensing, Landslide detection etc. In this paper we are detecting and preventing black hole attack, gray hole attack, misdirection attack and DOS attack. For prevention of all these attacks we are using one protocol which is LEACH protocol. LEACH protocol means Low Energy Adaptive Clustering Hierarchy. This protocol uses limited energy which increases the network lifetime.