The Vehicular Ad-hoc NETwork (VANET) consists of mainly three component, they are Trusted Authority (TA), Road Side Unit (RSU) and onboard unit located inside the vehicles. VANET enables vehicles to communicate with each other and with RSUs. Security is a major problem in VANET. This paper focused on insider attacks. The insider attackers enter into the network and send some wrong messages. It results accidents; traffic block and may damages whole system of the network. The existing system of this paper shows the demonstration of insider attacks and the detection of malicious nodes using consistency checking.