In today's digital world, companies and organizations rely heavily on cloud computing for their everyday needs. Ensuring availability, confidentiality, accessibility, and integrity in the cloud is crucial. Any attack on cloud services can lead to serious consequences, including downtime, reputational damage, and financial loss. Among these threats, Distributed Denial of Service (DDoS) attacks are particularly concerning as they target cloud infrastructure with overwhelming traffic. This review examines various studies on cloud architecture and DDoS attack scenarios, exploring how these attacks happen and their impact. It also discusses defensive measures like mitigation, detection, and prevention, while acknowledging the limitations of existing research in fully addressing DDoS threats.