Many application areas of Mobile Ad Hoc Networks (MANET) depend solely on group communication. In a MANET, multicast communication is intended specially for group-based communications with minimum bandwidth utilisation. Security issues relating to multicast communication have become sterner, given the likelihood that forwarding nodes may be unauthenticated members of a multicast group. Current multicast protocols are designed only for cooperative communication environments, not always feasible in the real world. In this paper, we analyse possible security attacks and defence mechanisms followed in multicast communication of MANET. We compare, with respect to well-known attacks, presently available solutions to security attacks in unicast and multicast communications. Also, we analyse and classify security attacks into two types: (i) common attacks in both unicast and multicast routings, and (ii) multicast-specific attacks. The survey reported in this research paper can lay the groundwork for future research in this challenging field.