Updates

Author: msmbaldwin

articles/attestation/overview.md

@@ -10,7 +10,7 @@ ms.author: mbaldwin
 ms.custom: references_regions
 
 ---
-# Microsoft Azure Attestation 
+# Microsoft Azure Attestation
 
 Microsoft Azure Attestation is a unified solution for remotely verifying the trustworthiness of a platform and integrity of the binaries running inside it. The service supports attestation of the platforms backed by Trusted Platform Modules (TPMs) alongside the ability to attest to the state of Trusted Execution Environments (TEEs) such as [Intel® Software Guard Extensions](https://www.intel.com/content/www/us/en/architecture-and-technology/software-guard-extensions.html) (SGX) enclaves, [Virtualization-based Security](/windows-hardware/design/device-experiences/oem-vbs) (VBS) enclaves, [Trusted Platform Modules (TPMs)](/windows/security/information-protection/tpm/trusted-platform-module-overview),  [Trusted launch for Azure VMs](../virtual-machines/trusted-launch.md) and [Azure confidential VMs](../confidential-computing/confidential-vm-overview.md).
 
@@ -20,6 +20,8 @@ Azure Attestation enables cutting-edge security paradigms such as [Azure Confide
 
 Azure Attestation receives evidence from compute entities, turns them into a set of claims, validates them against configurable policies, and produces cryptographic proofs for claims-based applications (for example, relying parties and auditing authorities).
 
+Azure Attestation supports both platform- and guest-attestation of AMD SEV-SNP based Confidential VMs (CVMs). Azure Attestation-based platform attestation happens automatically during critical boot path of CVMs, with no customer action needed. For more details on guest attestation, see [Announcing general availability of guest attestation for confidential VMs](https://techcommunity.microsoft.com/t5/azure-confidential-computing/announcing-general-availability-of-guest-attestation-for/ba-p/3648228).
+
 ## Use cases
 
 Azure Attestation provides comprehensive attestation services for multiple environments and distinctive use cases.
@@ -40,17 +42,17 @@ Intel® Xeon® Scalable processors only support [ECDSA-based attestation solutio
 
 OE standardizes specific requirements for verification of an enclave evidence. This qualifies OE as a highly fitting attestation consumer of Azure Attestation.
 
-### TPM attestation 
+### TPM attestation
 
 [Trusted Platform Modules (TPM)](/windows/security/information-protection/tpm/trusted-platform-module-overview) based attestation is critical to provide proof of a platform's state. A TPM acts as the root of trust and the security coprocessor to provide cryptographic validity to the measurements (evidence). Devices with a TPM can rely on attestation to prove that boot integrity is not compromised and use the claims to detect feature state enablement during boot. 
 
 Client applications can be designed to take advantage of TPM attestation by delegating security-sensitive tasks to only take place after a platform has been validated to be secure. Such applications can then make use of Azure Attestation to routinely establish trust in the platform and its ability to access sensitive data.
 
-### AMD SEV-SNP attestation 
+### AMD SEV-SNP attestation
 
 Azure [Confidential VM](../confidential-computing/confidential-vm-overview.md) (CVM) is based on [AMD processors with SEV-SNP technology](../confidential-computing/virtual-machine-solutions-amd.md). CVM offers VM OS disk encryption option with platform-managed keys or customer-managed keys and binds the disk encryption keys to the virtual machine's TPM. When a CVM boots up, SNP report containing the guest VM firmware measurements will be sent to Azure Attestation. The service validates the measurements and issues an attestation token that is used to release keys from [Managed-HSM](../key-vault/managed-hsm/overview.md) or [Azure Key Vault](../key-vault/general/basic-concepts.md). These keys are used to decrypt the vTPM state of the guest VM, unlock the OS disk and start the CVM. The attestation and key release process is performed automatically on each CVM boot, and the process ensures the CVM boots up only upon successful attestation of the hardware.
 
-### Trusted Launch attestation 
+### Trusted Launch attestation
 
 Azure customers can [prevent bootkit and rootkit infections](https://www.youtube.com/watch?v=CQqu_rTSi0Q) by enabling [trusted launch](../virtual-machines/trusted-launch.md) for their virtual machines (VMs). When the VM is Secure Boot and vTPM enabled with guest attestation extension installed, vTPM measurements get submitted to Azure Attestation periodically for monitoring boot integrity. An attestation failure indicates potential malware, which is surfaced to customers via Microsoft Defender for Cloud, through Alerts and Recommendations.