1.4.1. Shared Responsibility: Microsoft's Role

💡 First Principle: The cloud provider is responsible for securing the foundational global infrastructure, including the physical data centers, networking, and host hardware/software that deliver all cloud services.

Scenario: A financial services company hosts its application on Azure App Service. They are concerned about the physical security of the data centers and the patching of the underlying App Service operating system.

In the Azure Shared Responsibility Model, Microsoft's responsibility is to protect the infrastructure that runs all of the services offered in Azure. This "security of the cloud" includes protecting the global infrastructure (Regions, Availability Zones) and the hardware, software, networking, and facilities that run Azure services.

Key Microsoft Responsibilities ("Security of the Cloud"):

• Physical Security: Data centers, servers, networking hardware.
• Network Controls: Global Azure network backbone and infrastructure.
• Host OS: Operating systems of the physical hosts providing Azure services.
• Virtualization Layer: The hypervisor that isolates customer Virtual Machines.
• Managed Services Infrastructure: Underlying infrastructure for Azure App Service, Azure Functions, Azure SQL Database, Azure Storage, etc. This includes patching and security configuration of these underlying hosts and platform components.

⚠️ Common Pitfall: Assuming Microsoft's responsibility extends to the guest OS on an IaaS VM. While Microsoft secures the host, the customer is responsible for patching and securing the operating system inside their virtual machine.

Key Trade-Offs:

• Abstraction vs. Visibility: Microsoft manages the underlying infrastructure, which simplifies operations for the customer but also means the customer has limited visibility into the physical hardware layer.

Reflection Question: How does Microsoft's "security of the cloud" responsibility, by managing the physical security and underlying infrastructure for managed Azure services (like App Service), enable a Solutions Architect to focus on higher-level application and data security design, rather than the foundational environment?