Cloud computing has transformed the IT landscape by providing scalable, flexible, and cost-effective services. However, its multi-tenant infrastructure introduces significant security and privacy challenges due to shared resources and virtualized environments. This paper examines established security and privacy frameworks, threat models, and protective architectures designed to address these concerns. Through a comparative analysis of existing literature and technical frameworks, the study identifies key vulnerabilities and effective mitigation strategies in multi-tenant cloud environments. Additionally, graphical models and charts are included to demonstrate how shared resource access and virtualization can be secured using encryption, tenant isolation, and dynamic authentication mechanisms.