Abstract: Mobile ad-hoc network is a continuously self configuring infrastructure fewer networks of mobile devices connected without wires. Each device in a MANETs is free to move independently in any direction and in therefore change its link to any other devices frequently. Each must forward traffic unrelated to its own use, and therefore be a router. The primary challenge in building a MANETs is equipping each device to continuously maintain the information required to properly route traffic and security. MANETs are usually setup in situations of emergency for temporary operations or simply if there are no resources to setup elaborate networks. As MANETs are deployed in adversarial environment there is no proper security to transmit the data securely. There are many types of attacks that causes while communication takes place between source and destination. Attacks are harmful against wireless ad-hoc network and delay tolerance network, in which a node illegitimately claims multiple identities in order to gain unfair influence. Attacks in MANETs can be classified as active and Passive Attack, Wormhole, Black hole, rushing attack etc. In this survey paper the different types of attacks in ad-hoc networks and security goals, MANET challenges, MANET security challenges and attacks in different layers have been discussed.

Keywords: MANETs,Adversarial, Delay Tolerance, Active Attack, Passive Attack, Wormhole, Black Hole,Rushing Security attacks.