Abstract: Cloud computing is the most emerging technology today. It is providing solution to various resources either software or hardware to its users’ on-demand in pay-as-you go strategy. Now-a-days every IT companies are focusing on adoption of this latest innovative computing trend. Using virtualization technique, network and storage, this computing provides number of services using shared pool of resources in distributed environment. Due to its advent over the Internet, this computing is also vulnerable to various attacks like Man-in-the middle attack, DoS attack, Session Hijacking, etc. and hence arises number of security concerns. This paper elaborates various security concerns and popular attacks in cloud. Beside this it also focus on various Intrusion Detection System available in cloud computing.

Keywords: cloud security, attacks, Intrusion Detection System (IDS), Denial of Service (DoS), Anomaly Based IDS, knowledge base IDS.