Cloud computing is a technology which provides computing power through the internet to the user. Through cloud computing the user can access on-demand computing power without the need to build or maintain their own physical infrastructure. Cloud computing is a very prospective technology which is continuously growing and all big companies are promoting and migrating to cloud based technologies. But since cloud computing is a technology based on networking as it provides cloud resources through the internet, it increases the level of network security risk, since the cloud environment is mostly provided by a third party cloud service provider. This makes securing a cloud application difficult and the data stored on the cloud vulnerable to attacks. This paper explains the cloud architecture, cloud service models, advantages of a cloud and discusses the cloud security issues and threats while also suggesting a few solutions and precautions for safeguarding data on the cloud through reviewing published works.