Cloud Computing emerges as one of the hottest topic in the field of information technology. Nowadays not just large organizations, but even small and medium size businesses are looking forward to adopt an economical computing resource for their business application, i.e. by introducing a new concept of cloud computing in their environment. Basically it’s a new concept of providing virtualized resources to the consumers. Cloud Computing is a set of IT services that are provided to a customer over a network on a leased basis and with the ability to scale up or down their service requirements. Usually Cloud Computing services are delivered by a third party provider who owns the infrastructure.Consumers can request a cloud for services, applications, solutions and can store large amount of data from different location. Cloud Computing holds the potential to eliminate the requirements for setting up of high-cost computing infrastructure for ITbased solutions and services that theindustry uses. It promises to provide a flexible IT architecture; accessible through internet from lightweight portable devices.This would allow multi-fold increase in the capacity and capabilities of the existing and new software. This new economic model for computing has found fertile ground and is attracting massive global investment. Many industries, such as banking, healthcare and education are moving towards the cloud due to the efficiency of services provided by the pay-per-use pattern based on the resources such as processing power used, transactions carried out, bandwidth consumed, data transferred, or storage space occupied etc. Despite the potential gains achieved from the cloud computing, the organizations are slow in accepting it due to security issues and challenges associated with it. Security in Cloud Computing is an importantand critical aspect, and has numerous issues and problem related to it. Cloud service provider and the cloudservice consumer should make sure that the cloud is safe enough from all the external threats so that thecustomer does not face any problem such as loss of data or data theft. There is also a possibility where amalicious user can penetrate the cloud by impersonating a legitimate user, thus infecting the entire cloud andaffects many customers who are sharing the infected cloud. This research paper outlines what cloud computing is, the various cloud models and the parameters that affect thesecurity of the cloud. This extensive research also aims to elaborate the possible security attacks and the security issues that arise in a cloud computing frame work. It focuses on technical security issues arising from the usage of cloud services and also provides an overview of key security issues related to cloud computing with the view of a secure cloud architecture environment.