All posts in category HAADJ

Microsoft Intune Cloud PKI

Recently, Microsoft introduced the general availability of its new PKI-as-a-service solution called Microsoft Intune Cloud PKI. Cloud PKI allows administrators to issue and manage user and device authentication certificates for Intune-managed endpoints without deploying Active Directory Certificate Services (AD CS) on-premises. Cloud PKI frees administrators from the burdens of deploying and managing AD CS, including the complicated Network Device Enrollment Service (NDES) server configuration required for Simple Certificate Enrollment Protocol (SCEP) certificate deployment with Intune.

Advantages

Microsoft Intune Cloud PKI offers many significant advantages over traditional on-premises AD CS deployments.

No Infrastructure

The most obvious advantage of using Cloud PKI is that you do not have to deploy and manage your own Certification Authority (CA). Although implementing AD CS isn’t that difficult, managing and operating a CA infrastructure securely can be quite challenging. In addition, a high-security AD CS deployment utilizes hardware secure modules (HSMs) to protect CA private keys, which are quite expensive and sometimes difficult to support.

Cloud-Hosted SCEP

Removing the requirement to configure and deploy your own NDES server to support SCEP certificates is certainly a welcome advantage. NDES is notoriously difficult to configure, secure, and troubleshoot when it doesn’t work correctly. Cloud PKI includes cloud hosted SCEP services that are highly available and redundant within the Microsoft Azure infrastructure.

Automatic Revocation

Cloud PKI automates the deployment of certificates to Intune-managed users and devices and automatically revokes certificates when they fall out of scope. Administrators can also manually revoke certificates using the Intune management console.

Reporting

Administrators can easily view the status of Cloud PKI-issued certificates in Intune. The UI shows the active, expired, and revoked certificates for the issuing CA.

Clicking View all certificates shows a detailed list of all certificates.

BYOCA

Another compelling feature of Cloud PKI is Bring Your Own CA (BYOCA). This feature enables administrators to deploy a cloud-hosted CA that is chained to their existing on-premises AD CS root CA. This is helpful for scenarios where AD CS is already in place and used to issue and manage certificates to existing domain-joined clients and servers. BYOCA effectively allows you to extend your existing CA infrastructure to the cloud and use Cloud PKI to issue and manage certificates for your Intune-managed endpoints while maintaining the full functionality and feature set of on-premises AD CS for non-Intune-managed devices.

Limitations

Although there are many advantages to Cloud PKI, there are some limiting factors to consider.

RSA Only

Today, Cloud PKI is limited to RSA keys only. Administrators can create CAs using RSA 2048, 3072, or 4096-bit keys. Elliptic Curve (EC) keys are not currently supported in Cloud PKI.

Intune Devices Only

Cloud PKI is limited to issuing certificates to Intune-managed devices only. Endpoints must be Entra-joined, or hybrid Entra-joined to enroll for certificates using Cloud PKI.

Inflexible Configuration

The Cloud PKI root and issuing CAs cannot be reconfigured after deployment. Since Cloud PKI root and issuing CAs don’t support the Any Purpose EKU (2.5.29.37.0), all EKUs must be defined when the CA is created. If, in the future, an administrator requires an EKU that was not present when the CA was deployed, an entirely new hierarchy (root and issuing CA) must be deployed.

No Strong Mapping

As of this writing, Cloud PKI does not yet support strong certificate mapping for KB5014754. Microsoft fixed this limitation with Entra Conditional Access certificates and is working to include support for SCEP and PKCS. Hopefully, this shortcoming will be addressed soon in Cloud PKI.

Cost

There’s been much discussion about the cost associated with Cloud PKI. Cloud PKI can be licensed as part of the Intune Suite, which is $10.00 per user per month. Cloud PKI licenses will also be available as a standalone add-on for $2.00 per user per month. For large organizations, this might be cost-prohibitive.

Summary

Overall, Microsoft Intune Cloud PKI is a welcome addition to the Microsoft suite of cloud services. Certificates are excellent phishing-resistant credentials that can be used to improve security for organizations of all sizes. However, managing a CA can be tedious and time-consuming. Leveraging the cloud for PKI and certificate management will be helpful in many scenarios. However, Cloud PKI has some potential drawbacks, and many may not fit everyone.

More Information

Want to learn more about Microsoft Intune Cloud PKI and how it can benefit your organization? Take the first step towards streamlined certificate management and enhanced security for your organization. Fill out the form below, and I’ll provide more information about using Intune Cloud PKI to safeguard your digital assets confidently.

2 Comments

by Richard M. Hicks on March 18, 2024 • Permalink

Posted in Active Directory, Active Directory Certificate Services, AD CS, administration, authentication, Azure, Azure Active Directory, Certificate Authentication, Certificate Authority, Certificate Connector for Intune, Certificate Services, certificates, cloud, Cloud PKI, Cloud Service, Cryptography, Device Management, Encryption, Endpoint Manager, Enterprise, enterprise mobility, Entra, Entra ID, HAADJ, Hybrid Azure AD Join, Infrastructure, InTune, Intune Certificate Connector, Intune PFX Connector, MDM, Microsoft, Microsoft Endpoint Manager, Microsoft Entra, Microsoft Entra ID, Microsoft Intune, Mobile Device Management, Mobility, Multifactor Authentiction, Network Device Enrollment Service, Network Device Enrollment Services, network policy server, NPS, Operational Support, PFX Connector, PKCS, PKI, public cloud, public key infrastructure, SCEP, Security, Simple Certificate Enrollment Protocol, systems management, TPM, troubleshooting, Windows 10, Windows 11

Posted by Richard M. Hicks on March 18, 2024

https://directaccess.richardhicks.com/2024/03/18/microsoft-intune-cloud-pki/

Considerations for Always On VPN with Azure VPN Gateway and Virtual WAN

Organizations migrating on-premises applications, data, and infrastructure to the cloud may also consider terminating Always On VPN connections there. Using one of the native Azure VPN services might be compelling at first glance. After all, having an Azure-managed VPN gateway service sounds intuitive. However, some severe limitations exist for using Azure VPN services for Always On VPN deployments.

Azure VPN Gateway

The following are limitations for Always On VPN with Azure VPN gateway.

Authentication Methods

Azure VPN gateway supports both EAP and machine certificate authentication. However, it can only support one authentication method at a time. With only EAP or certificate authentication, administrators must choose between a device or user tunnel. A single Azure VPN gateway cannot support both at the same time. For native Entra ID joined devices, this is not a problem. However, for native on-premises Active Directory or hybrid Entra ID joined devices, this is a problem, as the device tunnel is essential in these scenarios.

Note: Technically speaking, administrators could deploy another Azure VPN gateway to work around this limitation. However, Azure limits VPN gateway deployments to one per virtual network. This requires administrators to deploy a second VPN gateway in a separate virtual network, which then requires virtual network peering to be enabled, complicating the configuration greatly.

SSTP

Although the Azure VPN gateway supports SSTP, it is, unfortunately, a second-class citizen. Today, all SKUs of the Azure VPN gateway are limited to just 128 SSTP connections (256 in active/active mode). There is currently no way to increase this. If more than 256 connections are required, you must use IKEv2.

RADIUS

In addition, there is currently no option to change the default timeout value (30 seconds) for RADIUS authentication requests. This short timeout value presents a challenge when using MFA with the NPS extension or with Azure Conditional Access, as users may be unable to respond to the push notification before the timeout expires, resulting in failed authentication attempts.

In addition, Azure does not support routing traffic to on-premises RADIUS servers over ExpressRoute connections. In this scenario, administrators must route RADIUS traffic to on-premises servers over a site-to-site connection.

Geographic Redundancy

Geographic redundancy using Azure Traffic Manager (or another global server load balancer) with two or more gateways is not supported when using the Azure VPN gateway. Azure manages the certificate used on the gateway, which includes a certificate with the subject name of the individual gateway. There is no option to supply a custom certificate with a global hostname in the subject, which is required to support geographic redundancy. With that, administrators are limited to the redundancy provided natively by the Azure VPN gateway.

IPv6

Azure does not support Azure VPN gateway in a virtual network that includes IPv6 addressing.

Azure Virtual WAN

Azure Virtual WAN includes many of the same limitations as the Azure VPN gateway, in addition to the following.

SSTP

Unlike the Azure VPN gateway, there is no support for SSTP in Azure Virtual WAN.

IPv6

IPv6 is not currently supported at all in Azure Virtual WAN.

Summary

Intuitively, it seems that leveraging native Azure VPN gateway services would be ideal. However, due to the limitations outlined in this article, administrators must decide carefully if any of these prevent adoption in their environment. Although not formally supported, many organizations deploy Windows Server Routing and Remote Access (RRAS) servers in Azure to address these limitations.

Additional Information

Always On VPN Options for Azure Deployments

Always On VPN with Azure Gateway

Always On VPN Device Tunnel with Azure VPN Gateway

Always On VPN and RRAS in Azure

What is Azure VPN Gateway?

What is Azure Virtual WAN?

Always On VPN and Interface Metrics

In Windows, each network interface identified by the operating system is assigned a metric value. Interface metrics are settings that determine the priority or preference of network interfaces when there are multiple active network connections. The Windows networking stack uses these metrics to determine which network interface should be used for routing traffic when multiple network interfaces are available. Network interface metrics are critical for Always On VPN administrators to understand because they can impact how name resolution requests are processed when an Always On VPN connection is established.

Metric Values

By default, Windows automatically assigns metric values to network interfaces (including VPN interfaces) based on various factors, including the connection speed, link state, and interface type. It tries to select the most suitable interface for general internet connectivity.

Metrics and DNS

Windows will also use the network interface with the lowest metric value as the preferred interface for sending DNS queries by default. This means that DNS queries will be routed through the network interface with the lowest metric value, assuming it is available and connected. When an Always On VPN connection is established, DNS queries may fail or return unexpected results if the network interface metrics are not configured optimally.

Split DNS and Wired Ethernet

Split DNS (sometimes called ‘split brain DNS’) is when the DNS namespace is the same internally and externally. The most common scenario where interface metric settings interfere with DNS operation is when using split DNS and the endpoint is connected to the Internet with a wired Ethernet connection. In this scenario, the Ethernet interface will be assigned the same or lower interface metric value as the Always On VPN interface, which can yield unexpected results.

Viewing Metrics

Always On VPN administrators can view currently assigned interface metric values by running the following PowerShell command.

Get-NetIpInterface

Assigning Metrics

Most Always On VPN administrators will never have to change interface metric settings. However, if your implementation uses split DNS and some of your endpoints connect using wired Ethernet connections, you may need to update the interface metric settings to ensure proper DNS operation. Choose a setting for the interface metric value that is lower than the wired Ethernet interface. I’ve used a value of ‘3’ without issue for many years. Use one of the following methods to update the interface metric for Always On VPN connections.

PowerShell

Updating interface metric settings in Windows can be accomplished by running the Set-NetIpInterface PowerShell command.

Set-NetIpInterface -InterfaceAlias <connection name> -InterfaceMetric 3

Note: Using PowerShell to assign the interface metric is not persistent! While this method is suitable for local validation testing, you should use one of the following methods to implement this change permanently.

Rasphone.pbk

To assign the interface metric permanently, Always On VPN administrators can edit the following settings in the rasphone.pbk configuration file.

IpInterfaceMetric=3

Ipv6InterfaceMetric=3

Administrators can automate updating this setting using the Update-Rasphone.ps1 PowerShell script. In addition, the following scripts can be used with Microsoft Intune remediation.

Detect-DeviceIpv4InterfaceMetric.ps1

Remediate-DeviceIpv4InterfaceMetric.ps1

Detect-DeviceIpv6InterfaceMetric.ps1

Remediate-DeviceIpv6InterfaceMetric.ps1

Detect-Ipv4InterfaceMetric.ps1

Remediate-Ipv4InterfaceMetric.ps1

Detect-Ipv6InterfaceMetric.ps1

Remediate-Ipv6InterfaceMetric.ps1