Pick up any magazine or visit almost any IT website or blog, user will be sure to see talk about Cloud Computing. The only problem is that not everyone agrees on what it is exactly. Every individual has different views, but still there is a growing trend of using cloud environments. However, adopting a cloud computing environment may have positive as well as negative effects. This paper primarily aims to highlight the major security issues which are contentious and may delay its adoption. So the authors carry out a survey to investigate the security mechanisms that are enforced by major cloud service providers.