Securing the Cloud is a common concern for information technologies

Securing the Cloud is a common concern for information technologies. A major challenge is when users of Cloud Computing rely on their suppliers for adequate security. Indeed, the data present the head of computer networking and all the responsible parts in information technology try to protect it from certain attacks. In general, the data are treated and stored clearly in the cloud.
Cloud computing is a new computing paradigm adopted by organizations of all scales due to its low cost and pay-as-you-go structure. Cloud computing can be defined as Internet-based computing, whereby shared resources, software, and information are provided to computers and other devices on demand.
The National Institute of Standards and Technology (NIST) defined five characteristics of cloud computing as on-demand self service, rapid elasticity or expansion, broad network access resource pooling, and measured service. Cloud computing offers three main layers such as: Software as a Service (e.g. Google Apps), Platform as a Service (e.g. Google App Engine, Microsoft’s Azure) and Infrastructure as a Service (e.g. Amazon Web Service, Open Nebula). There are number of users, who use the cloud services over the untrusted network. The applications over the cloud are increasing rapidly and along with these applications vulnerabilities and numbers of attacks are also increasing. In addition, cloud computing is distributed so it is more likely to face security threats and interaction as privacy violations, Denial of Service (DoS), and unauthorized access. One of the defense lines for such environment is applying Intrusion Detection System to protect cloud resources and services from intrusive activities.