Detection of Distributed Denial of Service Attack

Availability is one of the three main objectives of computer security, along with confidentiality and integrity. Availability can be defined as the ability to use the information or resource desired. Denial of service attack is a most popular attack which effect the availability. In our research we mainly focus on the analyzing two denial of service attacks specially gray hole attack and black hole attack. Wireless networks mainly consist of both mesh clients and mesh routers. We constrain our analysis to mesh routers which are static. We have accept both black hole attack and gray hole attack in mesh routers and analysis the network without and with the presence of attack routers. We examines the delivery ratio of packets and observe how the network is affecting in the existence of an attack router by simulating the scenario with AODV protocol. By keeping the history of number packets transmitted and the number of packets received the algorithm defines the number of packets dropped and defines the probability of attack. We test our algorithm in the existence of an attack router and identify the attack router.