Due to the fundamental characteristics, security is very crucial for wireless sensor networks. Wireless sensor network is used in military applications, environment monitoring, forest fire detection, health applications etc. It has received great attention due to the wide range of applications. Sensor nodes are vulnerable to many more attacks such as jamming, selective forwarding, Sybil, wormhole, sinkhole etc. Among all possible attacks wormhole is very dangerous because after launching wormhole an attacker can launch many more attacks. Research related to wormhole in sensor network has received much interest recently.