Journal of Computers Vol. 29 No. 2, 2018, pp. 1-6 doi:10.3966/199115992018042902001 1 A Survey on Sybil Attack Detection in Vehicular Ad hoc Networks (VANET) Zaid A. Abdulkader 1,2 , Azizol Abdullah 2* , Mohd Taufik Abdullah 2 , Zuriati Ahmad Zukarnain 2 1 Al Iraqia University, Baghdad, Iraq 2 Faculty of Computer Sciences and Information Technology Universiti Putra Malaysia, Selangor, Malaysia azizol@upm.edu.my Received 17 October 2016; Revised 7 March 2017; Accepted 30 March 2017 Abstract. The Vehicular Ad hoc Networks are a special type of ad hoc network, which along with lacking in infrastructure, contain communicating entities that move with different accelerations. Hence, this obstructs the establishment of more consistent end-to-end communicating pathways and efficiently transferring data. Therefore, the VANETs display many network concerns and show differing security challenges for obtaining a secure communication, ubiquitous connectivity, and reputed management systems that can affect the cooperation and the negotiation between the various mobile networks. This survey report studies some techniques reported by the researchers for the detection of the Sybil attack in the VANET systems. Keywords: intrusion detection system, mobile ad hoc network, Sybil attack, vehicular ad hoc network 1 Introduction The Vehicular Ad hoc Networks (VANET) are a special type of the Mobile Ad-hoc Networks (MANET) which can communicate between the neighbouring vehicles and the roadside equipment [1-3]. In the VANET network, the vehicles act as the communicating nodes which belong to the self-organising mobile network with no knowledge regarding anyone else’s presence and without any prior screening. These networks contain two node types: On-Board Units (OBUs) and the Road Side Units (RSUs). The OBUs are the radio devices which are installed in the moving vehicles; whereas the RSUs are installed on the roadside and contribute towards the network infrastructure. The RSUs act as the router between all the vehicular traffic. With the help of the Dedicated Short Range Communication (DSRC) radio devices, the OBUs link the vehicles to the RSUs [4]. Recently, it is seen that the VANETs are developing into one of the most appropriate mobile technologies. They are seen to be a very promising approach for the implementation of the wireless mobile technology. Also, it is a promising approach for implementing the Intelligent Transportation System (ITS). The VANETs are seen to differ from the MANETs significantly: they have a higher node mobility, a larger scale of mobile networks, a more dynamic and geographically constrained topology, a very strict deadline, slower deployments, unreliability in the channel conditions, sporadic node connectivity, a recurrent network fragmentation and driver behaviours [1-2, 5]. The main objective of the VANET technology is allowing a good communication between the vehicles. Hence, the nodes have to incorporate the radio interfaces for efficient communication. Also, a particular range spectrum has to be committed for exchanging the data in the VANET technology. For a node to become an important part of the VANET technology and communicate effectively, it needs certain specific features that help it collect information and inform the neighbours along with making appropriate decisions using the gathered information. These features include the cameras, sensors, Global Positioning * Corresponding Author