Yes — C:\inetpub\DeviceHealthAttestation\bin\hassrv.dll is a legitimate Windows component. It belongs to the Device Health Attestation (DHA) service, a Microsoft security feature introduced in Windows 10 and Windows Server 2016. The DLL is part of the server role that validates a device’s Trusted Platform Module (TPM) and boot measurements, then issues a health attestation report.
🔍 What Device Health Attestation Does
- Purpose: DHA verifies that a device booted securely (e.g., Secure Boot, BitLocker, ELAM checks) and that the Windows kernel wasn’t tampered with.
- Integration: It works with Mobile Device Management (MDM) solutions and Active Directory/Entra ID to enforce compliance policies.
- Deployment: Microsoft offers DHA as:
- A cloud service (Microsoft-managed, free).
- An on-premises server role (installed on Windows Server, where
hassrv.dllis part of the role). - An Azure-hosted service.
📂 Why You See It in C:\inetpub\DeviceHealthAttestation
- The DHA server role installs into IIS (
inetpub) because it exposes a web API endpoint for devices to submit attestation requests. - The
hassrv.dllfile is the Health Attestation Service library that processes those requests. - Reports from admins confirm that copying
hassrv.dllfrom Server 2016 is sometimes used to fix DHA role issues on newer Server versions. - Microsoft’s own documentation and patch notes reference this file as part of the DHA feature.
✅ Safety Assessment
- Safe if installed by Windows Update or Server Role Manager: It’s a signed Microsoft DLL, not malware.
- Check digital signature: Right‑click → Properties → Digital Signatures tab. It should be signed by Microsoft Windows.
- Context matters: If you didn’t manually place it there and it appeared after a Windows update or server role installation, it’s expected and safe.
In short: hassrv.dll is a normal part of Microsoft’s Device Health Attestation service. If it’s digitally signed by Microsoft and located under C:\inetpub\DeviceHealthAttestation\bin\, you can consider it safe.