Security is becoming an important issue in cloud environment. Attackers can explore vulnerabilities of a cloud system and compromise virtual machines to deploy further large scale Distributed Denial of Service (DDoS). To prevent vulnerable virtual machine from being compromised in cloud a multi-phase distributed vulnerability detection, measurement and countermeasure selection mechanism called NICE have been proposed. Now-a-days, these systems are used by number of organizations to detect the weaknesses threats and preventing them. For this purpose, these systems became an important part of the security in nearly every organization.