Understanding cloud security models and architectures is essential for anyone starting in cloud protection. These models provide the foundation for how security is structured, managed, and enforced in cloud environments.

Understanding IaaS, PaaS, and SaaS Security

Cloud services are typically offered in three main models: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). Each model provides different levels of control and security responsibility for you and the cloud provider.

IaaS: Infrastructure as a Service

With IaaS, you rent basic computing resources such as virtual machines, storage, and networks. You install and manage your own operating systems, applications, and data.

Security responsibilities for IaaS:

• Manage the security of your operating systems and applications;
• Configure firewalls, access controls, and network security groups;
• Apply patches and updates to your software;
• Protect your own data from unauthorized access.

The cloud provider secures the physical infrastructure, virtualization layer, and foundational networking.

PaaS: Platform as a Service

PaaS offers a managed environment for developing, running, and deploying applications. The provider manages the servers, operating systems, and much of the middleware, while you focus on your application code and data.

Security responsibilities for PaaS:

• Secure your application code and data;
• Manage user access to your applications;
• Configure application-level security settings;
• Monitor for vulnerabilities in your own code.

The provider handles security for the underlying platform, operating system, and runtime environment.

SaaS: Software as a Service

With SaaS, you use fully managed software applications over the internet. The provider handles everything from infrastructure to application maintenance.

Security responsibilities for SaaS:

• Manage user access and permissions within the application;
• Protect sensitive data you store in the application;
• Understand and configure available security features, such as multi-factor authentication.

The provider is responsible for securing the application, underlying platform, and infrastructure.

Key Differences in Security Responsibility

• IaaS: You have the most control and responsibility for security.
• PaaS: You manage your application and data security, but not the platform.
• SaaS: You focus mainly on user and data security; the provider manages almost everything else.

Always understand your shared responsibility model to avoid security gaps. Each model shifts certain tasks to the provider, but you are always responsible for securing your own data and user access.