AZ-500 Microsoft Azure Security Technologies Exam

Implement and Validate Disk Encryption Solutions

Azure offers several disk encryption methods to protect data at rest on virtual machines. Azure Disk Encryption uses BitLocker on Windows VMs and DM-Crypt on Linux VMs to secure both OS and data disks. Server-Side Encryption (SSE) is always on and protects disks within storage clusters. When you enable encryption at host, SSE is extended to temporary disks and disk caches. For extra security, confidential disk encryption provides a hardware-backed layer by tying keys to a virtual TPM.

Azure Disk Encryption integrates deeply with Azure Key Vault to manage the encryption keys and secrets. It supports customer-managed keys and a Key Encryption Key (KEK) option for an extra layer of protection. Administrators can rotate and control their keys to meet compliance and enforce separation of duties. Correct group policy settings and BitLocker external key protectors are also essential to avoid deployment failures.

When you activate encryption at host, Azure ensures end-to-end protection for all VM storage parts. This includes:

• Temp disk encryption for ephemeral data
• Disk cache encryption for performance
• Encrypted data flows between compute and storage nodes
  You can select platform-managed keys or use a customer-managed key in a Disk Encryption Set (DES) to meet your compliance requirements.

To protect highly sensitive workloads, Azure offers confidential VM encryption via Azure Confidential Compute. This solution encrypts the OS disk at the hardware level, locking keys to an attested VM state through a virtual TPM. This design isolates the VM from the hypervisor and host OS for enhanced key protection and secure execution. Support for the temporary disk on confidential VMs is currently in preview.

Validating and monitoring encryption status is key to a strong security posture. Use Azure Policy definitions to audit or enforce encryption at host, SSE with customer-managed keys, and confidential OS disk encryption. Continuous monitoring through Microsoft Defender for Cloud and Key Vault logs ensures that any compliance drift is detected. This combined approach provides visibility and ongoing protection for your encrypted disks.

Conclusion

In this section, we covered how to configure disk encryption in Azure using multiple methods. We looked at Azure Disk Encryption for Windows and Linux, encryption at host for complete VM disk protection, and confidential disk encryption for hardware-rooted security. We reviewed the role of Azure Key Vault in key management and the use of customer-managed keys and Disk Encryption Sets. Finally, we discussed validating encryption through Azure Policy and monitoring tools to maintain a strong security posture.