In which cloud deployment model does platform security come under the enterprise's responsibility?

In the Infrastructure as a Service (IaaS) cloud deployment model, platform security falls under the enterprise's responsibility. In an IaaS environment, the cloud provider offers the underlying infrastructure, including virtual machines, storage, and networking resources, but the organization using the service manages the operating systems, applications, and data. This means that security measures for the platform, such as configuring firewalls, managing identity and access management, and ensuring secure configurations, are the responsibility of the enterprise.

The other models have differing degrees of responsibility. For instance, in Software as a Service (SaaS), the provider manages much of the security, making the enterprise's role primarily about using the software securely. Similarly, in Platform as a Service (PaaS), while the enterprise has some control, much of the underlying security management is handled by the provider. In Network as a Service (NaaS), the focus is primarily on network-related capabilities, with varying responsibilities depending on the service agreement. Overall, IaaS offers the highest level of control and, consequently, responsibility for security at the platform level, making it essential for enterprises to understand and effectively manage these security requirements.