As cloud becomes the tool of choice for more data storage services, the number of service providers has also increased. With these choices, organisations have a wide selection of services available to move their data to the cloud. However, the responsibility to maintain the security of sensitive data stored therein remains paramount. This paper will discuss some of the challenges of securing a cloud storage and putting it into context by reviewing relevant literature. The challenges associated with the three important security aspects (confidentiality, integrity and availability) are discussed together with the vulnerabilities linked to them. It is important to look into these challenges as cloud storage is not only about technological evolution but involves security considerations. We aim to provide insights of security challenges and its solutions to enhance cloud storage implementation.