[Neela, 2(8): August, 2013] ISSN: 2277-9655 Impact Factor: 1.852 http: // www.ijesrt.com (C) International Journal of Engineering Sciences & Research Technology [2070-2072] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY Cloud Computing: Threats and Security Issues K.L.Neela *1 , V.Kavitha 2 , R.K.Ramesh 3 *1 Assistant Professor, Department of CSE, University college of Engineering, Thirukkuvalai, Tamil Nadu, India 2 Associate Professor, Department of CSE, University College of Engineering, Nagercoil, Tamil Nadu, India 3 Assistant Professor, Department of MCA, PET Engineering college, Trunelveli, Tamil Nadu, India klneela@yahoo.com Abstract Cloud Computing is an emerging concept in global IT world. It refers to a computing system in which the task is assigned over the internet by on-demand and pay on utilization basics. Most organizations are not willing to accept the cloud computing concept due to some security issues, even though some potential gain is there in cloud computing. Security is one of the primary issues which hamper the growth of the cloud. Due to the lack of security, it is difficult to maintain the sensitive and confidential data of users. This paper introduces a detailed analysis of cloud computing security risk and threats associated with it, which are affecting the various stake-holders linked to it. Keywords: Cloud Computing, IaaS, PaaS, SaaS, Public cloud, Private Cloud. Introduction Several trends are opening up the era computing, which is an Internet-based development and use of computer technology. The ever cheaper and more powerful one is cloud computing. Cloud computing' is a somewhat imprecise term to describe users 'renting' or borrowing online software. By this we can easily avoid Purchasing and installing software on our machines. It is the same business model as people using Gmail or Yahoo mail services, but the cloud computing concept goes some more extend by including daily computing activities. Most of the employees run their computer tool as online rented product. All action like processing work, saving files were done in cloud of the internet and user will connect to the cloud and do their day to day activities. Cloud computing services are available in almost all computer system aspects. A definition for Cloud computing was published by The US National Institute of Standards and Technology(NIST) such as :Cloud computing is a model for enabling convenient, on-demand network access to a share pool of configurable computing resources(eg:networks,servers,storage,applications and services)that can be rapidly provisioned and released with minimal management effort or Service provider interaction[1].While the US NIST definition also includes three primary service models such as Infrastructure as a service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) which is shown in figure 1: Fig1: Service models of Cloud Computing a) Infrastructure as a service (IaaS): Infrastructure as a Service (IaaS) is a way of delivering Cloud Computing infrastructure – servers, storage, network and operating systems – as an on- demand service Ex: Amazon.com[2] b) Platform as a Service (PaaS): It is the set of tools and services designed to make coding and