Black hole and Gray Hole attacks in MANET: A Survey

Mobile Ad hoc Network is a wireless infrastructure less network formed using mobile nodes. It is a multi-hop relay network where data is forwarded from source to destination using intermediate mobile nodes. If these intermediate mobile nodes are malicious then various security attacks are feasible. Network layer attacks such as Black hole attack, Cooperative Black hole attack, Gray hole attack and Cooperative Gray hole attack are possible in MANET, because MANET routing protocols assume trusted and cooperative environment in the network. This paper discuss about different kinds of Black hole and Gray hole attacks in MANET and their countermeasures.