Cloud Computing provides a good model for the providers to deploy the computing infrastructure and applications on-demand. It offers greater flexibility to users by connecting to various computing resources and allowing access to IT enabled services. But it has the risk of privacy of user data and security. Thus security among the users of cloud is the most important concern. One of the security issue in cloud computing is data mining based attacks, which involves that the data can be analyzed continuously by an unanonymous person to get the valuable information. Using the single cloud provider this is a major problem among the clients in the cloud, because the outside attacker can analyze their data for a long time to gain the sensitive information. In this paper, we have given the data mining based attacks on cloud data and a method to prevent the attacks. In this paper, review of various data mining techniques is presented which can help achieve security of information on cloud. In today's fastest growing IT industry Cloud Computing is gaining much more popularity because the Cloud providers feel that it is very easy to manage the data in the cloud environment rather than normal web-sites in form of simple web pages. Every day the data seeking is being done by many users immensely. Here due to immense number of users seeking the data on daily basis there is a serious security concerns to the cloud providers as well as the data providers who put their data on the cloud computing environment. This paper provides solution of the security issues of cloud computing.