Received: March 15, 2018 183 International Journal of Intelligent Engineering and Systems, Vol.11, No.5, 2018 DOI: 10.22266/ijies2018.1031.17 Secured Routing Protocol for Mobile Ad hoc Networks to Defend Collaborative Black-hole and Gray-hole Attacks by Malicious Nodes Madugundu Neelakantappa 1 * Amjan Shaik 2 1 Department of Information Technology, B.V.Raju Institute of Technology, Narsapur, Medak, Telangana State, India 2 Department of Computer Science & Engineering, B.V.Raju Institute of Technology, Narsapur, Medak, Telangana State, India * Corresponding author’s Email: m.neelakanta@gmail.com Abstract: Mobile Ad hoc Network (MANET) is a ubiquitous, infrastructure less and self-containing wireless network. In this networks nodes that are in mobility forms a temporary network without any infrastructure. In MANETs every node acts as host as well as router and therefore communication can be established on need basis without use of any fixed network equipment. But in presence of malicious nodes, this network leads to major security concerns as these nodes may disrupt the process of routing. In this scenario, detecting or preventing malevolent nodes, launching collaborative gray-hole or black-hole attacks is a major challenge. In this paper, a new secured routing protocol referred to as “Malicious Node Detection by Collaborative Bait (MNDCB)”. This protocol can be regarded as hybrid protocol as it poses the advantage of both reactive and proactive defending architectures. This MNDCB protocol is defined with a reverse tracking method to detect the malicious nodes and there by defending their collaborative attacks. Simultaneous results proves that in the presence of malevolent node attacks, the MNDCB gives better performance over their best counter parts base DSR, 2-ACK and best effort fault tolerant (BFTR) routing protocols in-terms of performance metrics: packet-delivery-ratio, throughput and routing overhead. Keywords: Black-hole, Gray-hole attacks, Malicious nodes, MANET security, Proactive and reactive defend architecture. 1. Introduction As mobile devices are widely available, Mobile Ad hoc Networks (MANETs) [1, 2] have been widely used in variety of applications like military operations, disaster recovery and commercial applications. Infrastructure less property is to the primary cause for its wide-spread applications. In MANETs every node will act as a host as well as a router. Due to absence of base stations, every node need to forward the packets of other nodes their by forming a wireless Local Area Network [2]. But, these features invite serious threats to the network in terms of security. These applications impose certain rigid constraints on the security of the routing, data traffic and network topology. For example, the existence of malevolent nodes and their collaboration may lead to disrupt the routing process, which intern leads to mal-functioning of the network operations. Extensive research work has been carried out on the MANETs security. Much of this work is focused on dealing with detection and prevention approaches to face individual malicious nodes. In this context, these techniques can’t be effective when dealing with multiple malicious nodes working together initiating a collaborative attack. In these cases, more devasting domains may result to the network. The dynamic topology added with infrastructure-less feature of ad hoc networks will make them highly vulnerable to attacks on routing like black-hole and gray-hole. As shown in Fig. 1, in black-hole attack, a malicious node transmits a falsie broadest informing that, it contains short path