Mobile Ad hoc Network (MANET) is one of the wireless networks where the access point is not present. Due to absence of administrator, the nodes may be comprised by the attackers. In the presence of active attackers, network may be damaged and out of connectivity. In the absence of passive attackers, information about the network may be disclosed to unauthorized agent. Compared to passive attackers, active attackers are most vulnerable to network. To detect and avoid this attacker, there is a need of reliable routing and intrusion detection system. In this work, Hybrid Cluster based Multicast Routing Approach (HCMRA) is introduced and implemented to detect and isolate the malicious attackers i.e. active attackers. In first stage, optimal path is identified through metrics of path to smooth packet delivery. In second stage, cluster is formed and cluster head is chosen based on energy and stability. Here sub CH is maintained to monitor routing, energy conservation etc. In third stage, trust aware routing is established in cluster region to identify the attackers based on reliability value. The work is simulated with various parameters like path reliability rate, end to end delay, packet delivery ratio, control overhead and energy efficienc