Cloud computing is the use of computing resources that are delivered as a service over a network. Today, cloud computing generates a lot of excitement. It is both promising and daunting. Businesses world see its potential but also have many issues for discussion. Cloud computing offers attractive financial and technological advantages but some of them has not been fully evaluated with respect to security. Security is considered one of the most critical aspects in cloud computing due to the sensitivity and importance of data stored in the cloud. Cloud Computing has several major issues such as data security, trust, expectations, regulations, and performance. This paper discusses the privacy and security issue of cloud computing and some existing security solutions about Distributed Denial-of- Service (DDoS) attacks, Intrusion Detection Systems (IDSs), Antivirus (AV), and Email Security, suggested by some researchers.