Security challenges in mobile ad hoc networks:a survey <s> Attacks <s> Mobile ad-hoc network (MANET) is one of the most promising fields for research and development of wireless network. As the popularity of mobile device and wireless networks significantly increased over the past years, wireless ad-hoc networks has now become one of the most vibrant and active field of communication and networks. Due to severe challenges, the special features of MANET bring this technology great opportunistic together. This paper describes the fundamental problems of ad hoc network by giving its related research background including the concept, features, status, and vulnerabilities of MANET. This paper presents an overview and the study of the routing protocols. Also include the several challenging issues, emerging application and the future trends of MANET. <s> BIB001 </s> Security challenges in mobile ad hoc networks:a survey <s> Attacks <s> Ad hoc Network is a self organized autonomous network that consists of mobile nodes which communicate with each other over wireless links .Wireless ad hoc networks are not well protected against the attack of malicious nodes due to security vulnerabilities in the routing protocols. One of the common attacks in MANETs is the Black hole Attack, in which malicious node falsely claiming it to have the fresh and shortest path to the destination and then drops all the receiving packets. If this malicious node work together as a group then the damage will be very serious. This type of attack is known as Cooperative Black Hole attack. We proposed a mechanism to mitigate single black hole attack as well as cooperative black hole attack to discover a safe route to the destination by avoiding attacks. In this paper we proposed an approach for better analysis and improve security of AODV, which is one of the popular routing protocols for MANET. Our scheme is based on AODV protocol which is improved by deploying Advanced DRI table with additional check bit. The Simulation on NS2 is carried out and the proposed scheme has produced results that demonstrate the effectiveness of the mechanism in detection and elimination of the attack and maximizing network performance by reducing the packet dropping ratio in network. <s> BIB002 </s> Security challenges in mobile ad hoc networks:a survey <s> Attacks <s> As a mobile ad hoc network (MANET) is dynamically formed by wireless mobile devices, which generally have limited computing resources, low network bandwidth accessibility, and limited power supply, and does not have any physical infrastructure and central base station, network management and operations are done cooperatively by all mobile devices in the network. In consequence, malicious mobile devices can easily join a MANET and launch attacks. Among those attacks, cooperative black hole attack requiring at least two malicious device nodes is a serious security threat since this attack is very easy to launch and hard to detect by other nodes. In this study, we introduce a secure routing protocol to defend against the cooperative black hole attack. Simulation experiments using QualNet has shown that our protocol provides up to 2.6 times performance in terms of the packet delivery ratio when comparing with AODV protocol under cooperative black hole attack. <s> BIB003
Due to special features like hop-by-hop communications, wireless media, open border and easy to setup, MANET became popular for malicious nodes. Some of the most important attacks in MANET are as follows: Black Hole Attack: In this attack, malicious node injects fault routing information to the network and leads packets toward itself, then discards all of them  BIB001 BIB002 . In  we present a survey on black hole detection and elimination approaches. Also we presented a classification of defeating approach for this attack. Authors in BIB003 presented a new approach based on confirming the best path using second path. In this approach, whenever a source node receives RREP packets, it send a confirmation packet through the second best path to the destination and ask the destination whether it has a route to the RREP generator or to the Next_Hop_Node of RREP generator or not. If the destination has no route to this nodes, both RREP generator and it's Next_Hop_Node will mark as malicious nodes. Using this approach source node can detect cooperative malicious nodes. Whoever in the case of more than two cooperative malicious node, this approach can't detect all malicious nodes.