Amongst various online attacks hampering JT security, Denial of Service has the most devastating effects. These attacks could be implemented diversely with с variety of tools and codes. This article represents implementing а Distributed attack such as “denial of service" based on cloud computing А comparison of the classical model of DDoS attacks and the attack model of clouds. In order to implement an attack using Amazon ЕС2. The author uses the technique of "Slow HTTP POST" tor the attack.