Security for any network is a primary concern as it is necessary to safeguard the resources that are being shared. A mobile ad-hoc network (MANET) enables the mobile devices to form a temporary network without any centralized infrastructure. MANET is vulnerable to several attacks, e.g. wormhole and blackhole attacks. Since there is increase in use of wireless communication, minimizing the intruders in wireless networks has been a high priority task. These attacks affect directly the performance of network. Eliminating such attacks in MANET is a challenging task. In this paper, a novel method that excludes the packets of wormhole and blackhole attacks in a MANET using fuzzy Lamport timestamp algorithm (FLTA) is proposed. The proposed FLTA is used to identify the order of event and to make synchronization of time clock in network device. The Lamport timestamp algorithm incorporates a fuzzy inference system to improve the performance of network. The simulated results of the proposed algorithm are compared with that of LTAWB [13] and SMTWB [12] for wormhole and blackhole attacks. It is observed that the proposed FLTA shows better performance as compared to LTAWB and SMTWB protocols in terms of throughput, end-to-end delay and packet delivery ratio