Vehicular Ad Hoc Networks (VANETS):Attacks and Challenges: A Survey Harish P. Chatar Prof. Surendra Waghmare PG Student,Dept.of E&TC Engg., G.H.Raisoni College of Engg. and Management, University of Pune, Pune,India HOD of E&TC Dept. G.H.Raisoni College of Engg. and Management University of Pune, Pune,India surendra.waghmare@raisoni.net harish.chatar201@gmail.com ABSTRACT Vehicular Ad-Hoc network have recently as one of the most important topic for research and automotive industries. Due to their high potential to improve safety traffic, efficiency and other added services. Authentication in vehicular Ad-Hoc network uses Public Key Infrastructure (PKI) to verify integrity of message and identity of message sender. In proxy based authentication security (PBAS) proxy vehicles are used to authenticate multiple messages with verification function at the same time. The issues considered in the authentication scheme included the level of security. This paper presents a survey of VANETs attack and message authentication using proxy vehicles and carefully considering the other similar work as well as update new attack and categorizing them into different class. may emerge due to the use of wireless devices in VANET communication. VANETs have a number of distinctive properties that could be also vulnerabilities for attackers to exploit. Those properties include the particular nature of communication in VANETs.Vehicular Ad hoc Network have attracted a lot of attention in research commute because of their varied value added services namely vehicle safety, automated toll payment, traffic management, travel lodge.[1] Keyword Vehicular Ad hoc Networks, Security Attacks, Challenges INTRODUCTION In the last few year, the massive deployment of wireless technology and the growing number of wireless product on motorized vehicles including remote keyless entry devices, PDAs, laptops, and mobile telephones have opened a number Varity of possibilities for both drives and their passengers.[1] The principle behind ad hoc networking is multi-hop relaying in which messages are sent from the source to the destination by relaying through the intermediate hops (nodes) VANETs have attracted a lot of attention due to its potential to offer better driving experience and road safety, as well as many other value added services.[3] Security issue is critical in VANETs because many different forms of attacks against VENETs Fig 1: Hierarchy of wireless ad hoc network OVERVIEW OF VANET 1. Intelligent transportation system(ITSs) :[6] In this each vehicle take the role of sender, receiver and route to broadcast the information to the vehicular network which than used the information to found safe, free flow of traffic. The communication occur between vehicles and roadside unit vehicle must be equipped with some short of onboard unit that enables the short range wireless Ad hoc network will be formed. Fixed RSUs which are connected to backbone network, must be in place to communication. The number and distribution of roadside unit is depend on communication protocol. These include inter vehicle, vehicle to roadside, and routing based communication. 2. Inter-vehicle communication:[6] The roadside unit may place at every kilometer, less & enabling high data rates to be maintained at heavy traffic. When broadcasting speed limit according to internal timetable and traffic condition. If a vehicle has a high speed limit, a broadcast will be delivered to the vehicle in the form of visual warning, that driver reduce his speed. The inter-vehicle communication used multi-hop broadcast to transmit the information related to traffic over a multihop to group of receiver. In transportation system, vehicle need only active on the road ahead and not behind. Fig 3:Vehicle-to-roadside communication 4. Routing based communication:[6] Fig 2: Inter-Vehicle Communication a) b) There are two types of message forwarding in inter-vehicle communication: Naïve broadcasting- In which vehicle send broadcast message periodically and regular interval of time. The vehicle ignores the message if it has come from a vehicle behind it. If the message comes from a vehicle in front, the receiving vehicle sends its own broadcast message to vehicle behind it. The limitations of the naïve broadcasting method is that large numbers of broadcast message are generated. Intelligent broadcasting- With implicit acknowledgement addresses the problems inherent in naïve broadcasting by limiting the number of messages broadcast for a given emergency event. The assumption is that the vehicle in the back will be responsible for moving the message along to the rest of the vehicles. If a vehicle receives a message from more than one source it will act on the first message only. 3. Vehicle-to-roadside communication:[6] In vehicle roadside communication it represent the single hop broadcast where the road side unit send a broadcast message to all equipped vehicle. Vehicle-to-roadside communication provide high bandwidth link between vehicle & roadside unit. Routing based communication is a multi-hop uncast where a message is propagated in a multi-hop fashion unit the vehicle carrying the desired data is reached. When the query is received by vehicle owing the desired information, the application at that vehicle immediately sends a uncast message containing the information to the vehicle is received the request form, which is then charge with the task of forwarding it toward the source. Fig 4:Routing based communication VANETs have a number of distinctive properties that could be also vulnerabilities for attackers to exports. Those property include the particular nature of communication in VANTEs. Connections in VANET in particular and in any wireless Ad Hoc network in general based of node to node communication: every node is able to act as either a host inquiring data or a router forwarding data. There are two types of Nodes:[1] 1) Roadside Units: Waiting for fixed nodes provisioned along the route component of that network then it separate the network in to two disconnect component.[2] 2) Onboard Unit: It consist of mobile node equipped with some radio interface that enables connecting to other nodes in wireless. Fig 6:Black hole Attack Gray hole attack: Fig 5:A basic Structure of VANET Gray hole attack has its own characteristic behavior .DATA packets, but nodes malicious activity is limited to certain condition. Two most common type of behavior. SECURITY CHALLENGES: Use of wireless links service in Ad-hoc network susceptible to link attack ranging passive to active impersonation, message replay & message distortion. Active attack could range from deleting message, injecting message, thus violating availability, integrity, authentication and non repudiation. We need to consider malicious attack not only from outside but also from within the network node. Following are the security can be breached. Vulnerability of channel: In wireless network, message can be eavesdropped and fake message can be injected into the network without difficulty of having physical to network component.[2] Vulnerability of nodes: As nodes do not reside in a protected place they can be easily captured and fall under the control of attack.[2] Absence of infrastructure: Ad-hoc network don’t work on fixed infrastructure, the classical security solution based on certification authorized.[2] Dynamically changing topology: It is difficult to distinguish that routing information change due to topology change.[2] Fig 7:Gray hole Attack a)Node dependent attack:-DATA packets toward a certain victim node or coming from certain node, while for other nodes it behaves normally by routing DATA packet ti the destination nodes correctly. SECURITY ATTACKS: Black hole attack: In this attacks a malicious acts like a Black hole, dropping all data packet passing through it as like mater and energy disappears from our universe in a black hole. If the attacking node is connecting node of two connecting Fig 7.1:Gray hole node dependent attack b)Time dependent attack:-DATA packet based on some trigger time while behaving normally during the other instance. connects via a warm hole link. In above figure Node X &Y performing warm hole attack.[2] Fig 8:Wram hole Attack Fig 7.2: Gray hole time dependent attack Rushing Attack: Jellyfish Attack: Jellyfish attack is somewhat different from Black-Hole & Gray-Hole attack. Instead of blindly dropping the data packet, it delays them before delivering them. It may even scramble the order of packet in which they are received and it in random order. Jellyfish attack can result in significance end to end delay and thereby degrading QoS. Few of method are used in this attack. a) One of the methods is scrambling packet order before delivering them instead of received FIFO order. ACK based flow control mechanism will generate duplicate ACK packet. b) Another method can be, performing selective Black-hole attack by dropping all packets at every RTO. This will caused timeout in sender node at every RTO for that duration. c) The attacking node can store all the received packet in its buffer but sends them after some random delay maintaining the received packet order. Sometime the source node might take a longer route instead of the most obvious shortest route. Warm hole attack: warm hole attack in cosmological term, connects two distant point in space via shortcut route. In the same way in MANET also one or more attacking node can disrupt routing by short circuiting the network, thereby disrupting usual flow of packets. Warm hole attack can be done with single node also but generally two or more malicious node In AODV or related protocol, each node before transmitting its data, first established a valid route to destination. Sender node broadcasts a RREO (route request) message in neighborhood and valid routes rely with RREP (route reply) with proper route information. Some of the protocols use duplicate suppression mechanism to limit the route request and reply chatter in network. In rushing attack, attacker node does send packet to proper node after its own filtering is done, so from outside the network behave normally as if nothing happened.[2] Fig 9: Rushing Attack Few of the protocols that might help in resolving Rushing attack: i) SEDYMO: Secured Dynamic MANET On. Demand is similar to DYMO but it dictates intermediate node must add routing information while broadcasting the routing message and no intermediate node should delete. ii) SRDP: Secure Route Discovery Protocol is security [6]Sherali Zeadally, Ray Hunt, Yuh-Shyan Chen, Angela enhanced Dynamic Source routing (DSR) protocol. Irwin, Aamir Hassan,”Vehicular Ad Hoc Networks: Status, iii) SND: Secure Neighbor Detection is another method of verifying each neighbor’s identity within a maximum transmission range. Result, and Challenges”,in Telecommunication System, Volume 50,Issue 4,app 217-241,2012. [7] P. Enge, Retooling the Global Positioning System, Scientific American (May) (2004). CONCLUSION: [8] J.T. Isaac, S. Zeadally, and J.S. Cmara, “security attacks Security in ad hoc networks is a very challenging issue. Because of their characteristics, ad hoc networks, are open especially to Denial of service attacks.[1]Classical security solutions are not suited for ad hoc networks.Basic Mechanisms A)Difficult to force the nodes to collaborate B)No standard routing protocol yet . Because of their characteristics, ad hoc networks are open especially to Denial of service attacks. Consists of vehicle-to-vehicle, vehicle-to-infrastructure communication. It improves the safety of vehicles. Supports Intelligent Transportation system. and solutions for vehicular ad hoc network”,in IET solution in vehicular AD HOC Network: A Survey” International Journal on Ad Hoc Network System Vol.4, No.2, April 2014. [2] Sanjana Lakkadi, Amit Mishra, Manish Bhardwaj” Security in ad hoc networks” American Journal of Networks and Communications vol.2,No 3.1, January 16, 2015. [3] Yiliang Liu, Liangmin Wang, “Message Authentication Using Proxy Vehicles in Vehicular Ad Hoc Networks” IEEE Transactions On Vehicular Technology, vol.xxx Year 2014. [4]Raya, M. and Hubaux, J., “The Security of Vehicular in Proceedings of the 3rdACM Workshop on Security of Ad Hoc and Sensor Networks (SASN 2005), Alexandria, VA. [5] Harsch, C., Festag, A. & Papadimitratos, P., “Secure Position-Based Routing for VANETs”, in Proceedings of 66thVehicular Technology Conference (VTC- 2007).Gerlach, M., Full Paper: Assessing and Improving Privacy in VANET’s Authentication in Vehicular Ad hoc Networks: ECDSA Based Approch”, in International Conference on Future Computer and communication,2009, pp. 16-20. [10] Sherali Zeadally ,Ray Hunt ,Yuh-Shyan Chen ,Angela Irwin ,Aamir Hassan “Vehicular ad hoc networks (VANETS): status, results,and challenges”Telecomm Syst [11] Security for Ad Hoc Network, Hang Zhao. [1] Vinh Hoa LA, Ana Cavalli “Security Attacks and IEEE [9] S.S. Manvi, M. S. Kakkasageri, D. G. Adiga, “Message DOI10.1007/s11235-010-9400-5. REFERENCES Ad Hoc Networks”, Communication, pp. 894-903,2009. www.network de/downloads/escar2006 herlach.pdf. konwheels