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title, description, ms.prod, ms.mktglfcycl, ms.sitesec, ms.pagetype, author, ms.localizationpriority, ms.date
| title | description | ms.prod | ms.mktglfcycl | ms.sitesec | ms.pagetype | author | ms.localizationpriority | ms.date |
|---|---|---|---|---|---|---|---|---|
| VPN and conditional access (Windows 10) | tbd | w10 | deploy | library | security, networking | jdeckerms | high | 07/27/2017 |
VPN and conditional access
Applies to
- Windows 10
- Windows 10 Mobile
The VPN client is now able to integrate with the cloud-based Conditional Access Platform to provide a device compliance option for remote clients. Conditional Access is a policy-based evaluation engine that lets you create access rules for any Azure Active Directory (Azure AD) connected application.
Note
Conditional Access is an Azure AD Premium feature.
Conditional Access Platform components used for Device Compliance include the following cloud-based services:
-
[Azure AD Connect Health](https://azure.microsoft.com/documentation/articles/active-directory-Azure ADconnect-health/)
-
Windows Health Attestation Service (optional)
-
Azure AD Certificate Authority - It is a requirement that the client certificate used for the cloud-based device compliance solution be issued by an Azure Active Directory-based Certificate Authority (CA). An Azure AD CA is essentially a mini-CA cloud tenant in Azure. The Azure AD CA cannot be configured as part of an on-premises Enterprise CA.
-
Azure AD-issued short-lived certificates - When a VPN connection attempt is made, the Azure AD Token Broker on the local device communicates with Azure Active Directory, which then checks for health based on compliance rules. If compliant, Azure AD sends back a short-lived certificate that is used to authenticate the VPN. Note that certificate authentication methods such as EAP-TLS can be used.
Additional details regarding the Azure AD issued short-lived certificate:
- The default lifetime is 60 minutes and is configurable
- When that certificate expires, the client will again check with Azure AD so that continued health can be validated before a new certificate is issued allowing continuation of the connection
-
Microsoft Intune device compliance policies - Cloud-based device compliance leverages Microsoft Intune Compliance Policies, which are capable of querying the device state and define compliance rules for the following, among other things.
- Antivirus status
- Auto-update status and update compliance
- Password policy compliance
- Encryption compliance
- Device health attestation state (validated against attestation service after query)
The following client-side components are also required:
- HealthAttestation Configuration Service Provider (CSP)
- VPNv2 CSP DeviceCompliance node settings
- Trusted Platform Module (TPM)
VPN device compliance
Server-side infrastructure requirements to support VPN device compliance include:
- The VPN server should be configured for certificate authentication.
- The VPN server should trust the tenant-specific Azure AD CA
- Either of the below should be true for Kerberos/NTLM SSO:
- Domain servers trust Azure AD CA
- A domain-trusted certificate is deployed to the client device and is configured to be used for single sign-on (SSO)
After the server side is set up, VPN admins can add the policy settings for conditional access to the VPN profile using the VPNv2 DeviceCompliance node.
Two client-side configuration service providers are leveraged for VPN device compliance.
- VPNv2 CSP DeviceCompliance settings
- Enabled: enables the Device Compliance flow from the client. If marked as true, the VPN client will attempt to communicate with Azure AD to get a certificate to use for authentication. The VPN should be set up to use certificate authentication and the VPN server must trust the server returned by Azure AD.
- Sso: nodes under SSO can be used to choose a certificate different from the VPN authentication certificate for Kerberos authentication in the case of device compliance.
- Sso/Enabled: if this field is set to true, the VPN client will look for a separate certificate for Kerberos authentication.
- Sso/IssuerHash: hashes for the VPN client to look for the correct certificate for Kerberos authentication.
- Sso/Eku: comma-separated list of Enhanced Key Usage (EKU) extensions for the VPN client to look for the correct certificate for Kerberos authentication.
- HealthAttestation CSP (not a requirement) - functions performed by the HealthAttestation CSP include:
- Collects TPM data used to verify health states
- Forwards the data to the Health Attestation Service (HAS)
- Provisions the Health Attestation Certificate received from the HAS
- Upon request, forwards the Health Attestation Certificate (received from HAS) and related runtime information to the MDM server for verification
Client connection flow
The VPN client side connection flow works as follows:
When a Device Compliance-enabled VPN connection profile is triggered (either manually or automatically):
- The VPN client calls into Windows 10’s AAD Token Broker, identifying itself as a VPN client.
- The Azure AD Token Broker authenticates to Azure AD and provides it with information about the device trying to connect. The Azure AD Server checks if the device is in compliance with the policies.
- If compliant, Azure AD requests a short-lived certificate
- Azure AD pushes down a short-lived certificate to the Certificate Store via the Token Broker. The Token Broker then returns control back over to the VPN client for further connection processing.
- The VPN client uses the Azure AD-issued certificate to authenticate with the VPN server.
Configure conditional access
See VPN profile options and VPNv2 CSP for XML configuration.
The following image shows conditional access options in a VPN Profile configuration policy using Microsoft Intune.
Note
In Intune, the certificate selected in Select a client certificate for client authentication does not set any VPNv2 CSP nodes. It is simply a way to tie the VPN profile’s successful provisioning to the existence of a certificate. If you are enabling conditional access and using the Azure AD short-lived certificate for both VPN server authentication and domain resource authentication, do not select a certificate since the short-lived certificate is not a certificate that would be on the user’s device yet.
Learn more about Conditional Access and Azure AD Health
- Azure Active Directory conditional access
- Getting started with Azure Active Directory Conditional Access
- Control the health of Windows 10-based devices
- Tip of the Day: The Conditional Access Framework and Device Compliance for VPN (Part 1)
- Tip of the Day: The Conditional Access Framework and Device Compliance for VPN (Part 2)
- Tip of the Day: The Conditional Access Framework and Device Compliance for VPN (Part 3)
- Tip of the Day: The Conditional Access Framework and Device Compliance for VPN (Part 4)