All posts tagged encryption

The Myth of the Publish Certificate in Active Directory Setting

Certificate templates in Microsoft Active Directory Certificate Services (AD CS) provide powerful, preconfigured settings that enable administrators to issue certificates tailored for specific purposes. For example, a certificate template could allow a user to authenticate to a Wi-Fi network or VPN gateway. Another template might control policies for enrolling for web server certificates in the enterprise. Templates define settings such as cryptographic parameters (key algorithm and length), validity period, application policies, enrollment requirements, and more. While there are myriad settings to choose from, one in particular is often enabled unnecessarily. And while it works without issue, there can be some hidden downsides to enabling this setting.

Publish Certificate in Active Directory

When creating a certificate template, there’s an option on the General tab called Publish certificate in Active Directory. From experience, this is one of the most misunderstood settings for certificate templates.

Intuitively, it would make sense to check this box on all published certificate templates. After all, I want the users or devices targeted by this certificate template to find them in Active Directory (AD) so they can enroll. Many administrators believe that enabling this setting is required to ‘see’ the published certificate template on the endpoint, as shown here.

However, enabling the Publish certificate in Active Directory option is not required for enrollment. To ‘see’ certificates available for enrollment, the user or device must only have the Enroll permission on the template.

What Is It For?

So, what does the Publish certificate in Active Directory setting do? When this option is enabled, the issuing CA adds the certificate to the requesting principal’s Active Directory account. There are two common scenarios where this is required.

S/MIME

Adding a user’s certificate to their AD account makes the public key centrally discoverable, allowing Outlook and other S/MIME-enabled clients to automatically find recipients’ certificates for secure email encryption and signature validation. Without the certificate published in AD, users must manually exchange certificates, breaking seamless S/MIME encryption in most enterprise environments.

Encrypting File System (EFS)

Publishing a user’s EFS certificate to their Active Directory account allows Windows to locate the correct public key automatically when encrypting files. It ensures recovery agents and key archival processes function properly. Without the certificate in AD, EFS can fail to encrypt data consistently across machines or prevent access to encrypted files when users roam or recover profiles.

Drawbacks

There are very few scenarios outside of S/MIME and EFS that require the Publish certificate in Active Directory option to be enabled. However, enabling it doesn’t necessarily break anything, and this setting is often enabled by default (or carried over from the source template when duplicating), so administrators may miss this option. Issuing certificates in this way introduces some potential problems.

AD Database Bloat

Adding a certificate to each principal’s AD object increases the size of each object, thereby increasing the total size of the AD database. For organizations with large directories with hundreds of thousands or even millions of accounts, adding unnecessary data to each account can be very expensive in terms of database size, replication traffic, backup storage, and overall domain performance. Making matters worse, certificates published to AD live perpetually. They are not removed automatically when certificates are revoked or expire.

Service Accounts

Service accounts used for certificate enrollment, such as the Microsoft Intune Certificate connector, can be especially challenging. Here, if the Publish certificate in Active Directory setting is enabled on the Intune certificate template, the CA will add a certificate to the service account for every certificate it issues. While you can have many certificates associated with a single account, there is an upper limit, approximately 1250, based on my testing. After that, certificates will continue to be issued, but adding them to AD will fail.

Remediation

The following recommendations can help administrators correct this misconfiguration and limit its impact in their environment.

Disable Unnecessary Certificate Publishing

Administrators should clear the Publish certificate in Active Directory setting on all certificate templates that do not explicitly require it, such as those used for S/MIME or Encrypting File System (EFS). This prevents new certificates from being written to user or computer objects and does not require certificates to be reissued.

Remove Published Certificates

Administrators can remove unnecessary certificates from user, computer, and service account objects in AD to reduce object and overall AD database sizes. Perform the following steps to remove unneeded certificates.

  1. Open the Active Directory Users and Computers management console (dsa.msc) and double-click the target principal.
  2. Select the Published Certificates tab.
  3. Select a certificate (or all certificates) and click Remove.

Important Note: Use extreme caution when deleting certificates! Do not delete any certificates unless you are certain they are not required.

Managed Service Accounts

Managed Service Accounts in AD do not have a Published Certificates tab. Administrators can use the Attribute Editor to remove individual certificates from the userCertificate attribute on the account.

Managed Service Account Attribute Editor

Managed Service Account userCertificate Entries

Unfortunately, there is no option to view the certificate in the UI for Managed Service Accounts. To view detailed certificate information, see the PowerShell section below.

Existing Certificates Are Not Removed Automatically

Disabling the Publish certificate in Active Directory setting only stops future certificates from being published in AD. Certificates already written to Active Directory are never removed automatically, even after they expire or are revoked. In environments where this setting has been enabled for an extended period, large numbers of stale certificates often accumulate and continue to increase the AD database size.

Intune Certificate Connector Considerations

This issue is especially problematic for high-volume enrollment scenarios that use service accounts, such as the Microsoft Intune Certificate Connector. When publishing is enabled for Intune certificate templates, certificates issued on behalf of users are added to the service account, quickly leading to excessive certificate accumulation and potential attribute limits.

ADPrincipalCertificate PowerShell Module

Manually performing this cleanup at scale is impractical. To assist administrators with cleaning up unnecessarily published certificates, I’ve created the ADPrincipalCertificate PowerShell module. This module includes functions to enumerate AD accounts that include certificates, show and optionally export certificates for AD accounts, and remove published certificates. The module also includes a function to enumerate published certificate templates that include the Publish certificate in Active Directory option enabled. You can install the ADPrincipalCertificate PowerShell module from the PowerShell gallery by running the following command.

Install-Module -Name ADPrincipalCertificate -Scope CurrentUser

See the ADPrincipalCertificate GitHub repository for detailed usage information.

Summary

While the Publish certificate in Active Directory option is helpful for S/MIME and EFS deployments, it is unnecessary for most other scenarios and is often enabled when it isn’t needed. This results in the unnecessary addition of certificates to AD accounts, causing individual objects and the entire AD database to grow without benefit. Sadly, many vendor guides indicate that this setting is required when it often isn’t, so many environments suffer from this misconfiguration. Administrators should review the certificate template configuration and disable this setting when it isn’t needed. Additionally, use the ADPrincipalCertificate PowerShell module to perform cleanup, if required.

Additional Information

ADPrincipalCertificate PowerShell Module on GitHub

ADPrincipalCertificate PowerShell Module in the PowerShell Gallery

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by Richard M. Hicks on February 9, 2026  •  Permalink
Posted in Authentication and MFA, Certificate-Based Authentication, Cryptography, Intune Certificate Connector, Microsoft Intune, PKI, PowerShell, Windows Server
Tagged , , , , , , , , ,

Posted by Richard M. Hicks on February 9, 2026

https://directaccess.richardhicks.com/2026/02/09/the-myth-of-the-publish-certificate-in-active-directory-setting/

PKI Fundamentals with Microsoft AD CS Training Course

I’m excited to announce that I’ve partnered once again with the fine folks at the ViaMonstra Online Academy to deliver a new live training course entitled PKI Fundamentals with Microsoft Active Directory Certificate Services (AD CS). The event consists of six weekly live webinars beginning on Thursday, January 15, 2026, at 3:00 PM CST.

Why AD CS Training?

Digital certificates are strong, phishing-resistant credentials that are an excellent choice for authentication to critical workloads like Always On VPN and enterprise Wi-Fi. However, managing certificate services infrastructure can be daunting. This course provides administrators with a fundamental understanding of enterprise PKI with Microsoft AD CS.

Course Overview

The event format for this course consists of six weekly live sessions on Thursdays starting on January 15, 2026. The classes are two hours long, running from 3:00 PM CST to 5:00 PM CST each day. During the course, we’ll cover the following topics.

  • PKI concepts and certificate use cases
  • Designing and deploying certificate authorities (CAs)
  • Configuring templates and enrollment
  • Managing revocation and maintenance

Who Should Attend

Organizations planning to use certificate authentication for enterprise VPN and Wi-Fi workloads will benefit from this training course. Also, those considering a new AD CS deployment will find this training beneficial. In addition, administrators managing an existing production AD CS environment will gain valuable insight.

Enroll Now

Registration for this training class is available now. The cost is $295.00—an incredible bargain! Don’t miss out on this fantastic opportunity to gain foundational AD CS skills. Click the registration link below and reserve your spot today!

Additional Information

Public Key Infrastructure (PKI)

Enterprise PKI

Cloud PKI for Microsoft Intune

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by Richard M. Hicks on November 6, 2025  •  Permalink
Posted in Authentication and MFA, Certificate-Based Authentication, PKI, TLS, Training and Events, Windows Server
Tagged , , , , , ,

Posted by Richard M. Hicks on November 6, 2025

https://directaccess.richardhicks.com/2025/11/06/pki-fundamentals-with-microsoft-ad-cs-training-course/

Intune SCEP Profile Changes for Public S/MIME Certificates

Recently, the CA/Browser Forum, which is a voluntary consortium made up of public CAs, browser vendors, and other industry stakeholders, introduced new requirements for S/MIME certificates issued by public certification authorities (CAs). For organizations using Microsoft Intune SCEP device configuration profiles to enroll for these certificates, administrators must update Intune settings to ensure uninterrupted enrollment once the changes take effect.

Subject Name Changes

Beginning July 16, 2025, all public CAs will enforce these new S/MIME Baseline Requirements, mandating “Given Name” and “Surname” attributes in the Subject Name field of S/MIME certificates. By default, Intune user certificate profiles include only the “UserName” attribute in the Subject Name field.

Intune Support

Intune recently completed the rollout of these new attributes in SCEP profiles. Administrators can now update their SCEP profiles for third-party public CAs to include these new attributes for S/MIME certificates using the following supported variables.

G={{GivenName}}
SN={{SurName}}

To align with current public CA standards, include these two fields along with any other information required in the Subject name format field. Multiple values must be separated by commas without spaces, as shown in the example below.

Private CAs

Private CAs, like Active Directory Certificate Services (AD CS) or Intune Cloud PKI, are unaffected. If you are enrolling for S/MIME certificates using these services, no changes are required.

Reenrollment

It’s important to note that modifying an existing Intune SCEP profile will trigger certificate reissuance for all users and devices within the policy’s scope, which could yield unexpected results. When making changes to Intune certificate policies, it is best to create a new policy to supersede the old one, allowing administrators to pilot the new policy before its broad deployment.

Additional Information

CA/Browser Forum S/MIME Baseline Requirements

Mastering Certificates with Microsoft Intune Training August 2025

Strong Certificate Mapping for Intune PKCS and SCEP Certificates

The Case for Short-Lived Certificates in Enterprise Environments

Always On VPN SSTP and 47-Day TLS Certificates

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by Richard M. Hicks on July 10, 2025  •  Permalink
Posted in Azure and AWS, Cloud PKI, Cryptography, Microsoft Intune, NDES and SCEP, PKI
Tagged , , , , , ,

Posted by Richard M. Hicks on July 10, 2025

https://directaccess.richardhicks.com/2025/07/10/intune-scep-profile-changes-for-public-smime-certificates/

Enable TLS in Microsoft SQL Server 2022

In a recent post, I described some of the security benefits of using Transport Layer Security (TLS) with Microsoft SQL Server. Configuration changes are required to take full advantage of these capabilities. By default, SQL Server uses an unmanaged, self-signed certificate, which provides little security value. The best practice is to use a certificate issued by the organization’s enterprise PKI. In this guide, I’ll demonstrate how to prepare and deploy a certificate template for SQL server using Active Directory Certificate Services (AD CS), enroll for the certificate, and configure SQL server to use the new certificate for TLS connections.

Note: I have recorded a video demonstration for enabling TLS in Microsoft SQL Server 2022 on my YouTube channel here. Enjoy!

Certificate Requirements

The minimum recommended requirements for a TLS certificate for SQL Server 2022 are:

  • Subject Name = Server’s fully qualified domain name or the alias name of the cluster
  • 2048-bit RSA key with SHA256
  • Server Authentication EKU (1.3.6.1.5.5.7.3.1)

Certificate Template

Administrators must prepare a certificate template in Active Directory (AD) adhering to the requirements listed above. On an issuing certification authority (CA) or an administrative workstation with the Remote Server Administration Tools (RSAT) installed, open the Certificate Templates management console (certtmpl.msc) and perform the following steps.

  1. Right-click the default Web Server template and choose Duplicate Template.
  2. Select the Compatibility tab.
    1. In the Compatibility Settings section, select the latest version of Windows Server supported by your issuing CA servers from the Certification Authority drop-down list.
    1. Select Windows 10/Windows Server 2016 from the Certificate recipient drop-down list.
  3. Select the General tab.
    1. Enter a descriptive name in the Template display name field.
    1. Select a validity period of 1 year with a renewal period of 6 weeks.
  4. Select the Cryptography tab.
    1. Select Key Storage Provider from the Provider Category drop-down list.
    1. Select RSA from the Algorithm name drop-down list.
    1. Enter 2048 in the Minimum key size field.
    1. Select SHA256 from the Request hash drop-down list.
  5. Select the Issuance Requirements tab.
    1. Check the box next to CA certificate manager approval.
  6. Select the Subject Name tab.
    1. Select Supply in the request.
  7. Select the Extensions tab.
    1. Select Application Policies.
    1. Ensure that Server Authentication is the only application policy listed.
  8. Select the Security tab.
    1. Click Add.
    1. Grant Read and Enroll permissions to the SQL Server security group or the SQL server’s computer account.
    1. Ensure no other users/groups have enroll permission.

Once complete, publish the certificate template on all issuing CA servers in the organization.

Enroll Certificate

The certificate enrollment process involves several steps.

Request Certificate

To enroll for a new TLS certificate, open the computer certificate management console (certlm.msc) on the SQL server and perform the following steps.

  1. Right-click on the Personal folder and choose All Tasks > Request New Certificate.
  2. Click Next.
  3. Click Next.
  4. Check the box next to the SQL server certificate template.
  5. Click the More information is required to enroll for this certificate. Click here to configure settings link.
  6. Select the Subject tab.
  7. In the Subject Name section, select Common Name from the Type drop-down list.
  8. Enter the SQL server’s fully qualified domain name (FQDN) or the alias name of the SQL cluster in the Value field.
  9. Click Add.
  10. In the Alternative name section, select DNS from the Type drop-down list.
  11. Enter the SQL server’s fully qualified domain name (FQDN) or the alias name of the SQL cluster in the Value field.
  12. Click Add.
  13. [OPTIONAL] Enter the SQL server’s single-label hostname in the Value field.

Certificate request Subject tab with the SQL server common name and DNS subject alternative names

Note: Adding the single-label hostname to the Subject Alternative Name list allows administrators or applications to connect to the SQL server using its short name (NetBIOS name) without resulting in a subject name mismatch error.

  1. Click Add.
  2. Click Ok.
  3. Click Enroll. The status should indicate that enrollment is pending.
  4. Click Finish.

Approve Certificate

Once the certificate request is made, the request must now be approved. On an issuing certification authority (CA), or an administrative workstation with the Remote Server Administration Tools (RSAT) installed, open the Certification Authority management console (certsrv.msc) and perform the following steps.

  1. Expand the CA.
  2. Select Pending Requests.
  3. Note the request ID for the pending request. After approval, the request ID will be required later to retrieve the certificate.
  4. Right-click the pending request and choose All Tasks > Issue.

Important Note: I am performing the above tasks in a test lab environment. On a properly configured CA in a production environment, the requestor should not be able to approve their own request. In your environment, you may need to request that a CA administrator review and approve your request.

Install Certificate

Once the certificate has been approved and issued, open an elevated PowerShell or command window on the SQL server and perform the following steps.

  1. Enter certreq.exe -retrieve <request ID>.
  2. Select the CA where the certificate was issued.
  3. Click Ok.
  4. Select a location and enter a name for the file in the File name field.
  5. Click Save.
  6. Enter certreq.exe -accept <path to certificate file>.
certreq.exe retrieving and accepting the issued SQL server certificate

Configure Certificate

Once the certificate has been enrolled on the SQL server, expand Personal > Certificates and refresh the view to confirm certificate enrollment. Next, perform the following steps.

  1. Right-click the SQL server certificate and choose All Tasks > Manage Private Keys.
  2. Click Add.
  3. Enter the name of the SQL server domain service account and click Check Names.
  4. If using the default SQL server service account, perform the following steps.
    1. Click on Locations.
      1. Select the local server.
      1. Click Ok.
      1. Enter NT Service\MSSQLSERVER and click Check Names.
  5. Click Ok.
  6. Uncheck Full control. The only permission required is Read.
  7. Click Ok.
Private key permissions granting the SQL Server service account Read access

SQL Configuration

Next, the new certificate must be assigned to the SQL Server service. Open the SQL Server Configuration Manager (sqlservermanager16.msc) and perform the following steps.

  1. Expand SQL Server Network Configuration.
  2. Right-click Protocols for MSSQLSERVER and choose Properties.
  3. Select the Certificate tab.
    1. Select the new certificate from the Certificate drop-down list.
  4. Select the Flags tab.
    1. Select Yes next to Force Strict Encryption.
  5. Click Ok.
SQL Server Configuration Manager Certificate tab with the new TLS certificate selected

SQL Server Configuration Manager Flags tab with Force Strict Encryption set to Yes

Restart the SQL Server service for the changes to take effect.

Important Note: Selecting Force Strict Encryption will force encryption and certificate validation for all clients connecting to the SQL server. It will override any settings to bypass encryption or certificate checks. Force Strict Encryption may not be compatible with older applications or drivers. Please test thoroughly before enabling this setting.

Video

I’ve published a demonstration video for configuring TLS on Microsoft SQL Server 2022 on YouTube. You can find the video here.

Summary

After completing the configuration steps above, administrators can be assured that all communication between clients and the SQL server is fully protected with TLS using modern cryptography and their enterprise-managed certificate. With TLS enabled for SQL server communication, security is enhanced by encrypting data in transit, ensuring authentication, and protecting sensitive information from interception. In addition, this configuration helps meet compliance requirements.

Additional Information

TLS and Microsoft SQL Server 2022

Always On VPN and SQL Target Principal Name Incorrect

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by Richard M. Hicks on March 3, 2025  •  Permalink
Posted in Authentication and MFA, Certificate-Based Authentication, Cryptography, PKI, TLS, Windows Server
Tagged , , , , , , ,

Posted by Richard M. Hicks on March 3, 2025

https://directaccess.richardhicks.com/2025/03/03/enable-tls-in-microsoft-sql-server-2022/

TLS and Microsoft SQL Server 2022

Transport Layer Security (TLS) for SQL Server 2022 has numerous benefits. TLS enhances SQL Server security by providing authentication, encrypting data in transit, ensuring regulatory compliance, and following security best practices. It helps prevent unauthorized access, protects sensitive information, and mitigates interception attacks, making it a critical component of a secure database environment.

Self-Signed Certificates

When installing Microsoft SQL Server 2022 on-premises, a self-signed certificate is automatically created to support Transport Layer Security (TLS) connections to the database. From a security perspective, using unmanaged, self-signed certificates is never a good idea.

Risk

Self-signed certificates are insecure because they are not issued by a trusted Certification Authority (CA), making it impossible to verify the legitimacy of the server. This lack of trust enables attackers to intercept and manipulate data through interception attacks. Additionally, since operating systems do not automatically trust self-signed certificates, users may ignore security warnings, increasing the risk of connecting to malicious or compromised servers.

Enterprise PKI Certificates

For production workloads, security best practices dictate using enterprise PKI-issued and managed certificates, which provide many security benefits.

Authentication

TLS with managed certificates provides a mechanism for server authentication, ensuring that clients connect to a legitimate server and not an impostor. TLS authentication helps mitigate interception attacks where an attacker could potentially impersonate the server. Managed TLS certificates can also be revoked in the event of key compromise.

Data Encryption

Microsoft SQL Server 2022 database servers often store sensitive data, including personal details, financial records, and other confidential business information. TLS ensures that data in transit between the client and the server is encrypted using modern cryptography, which enhances privacy and confidentiality while preventing unauthorized interception and eavesdropping.

Compliance Requirements

Many regulatory frameworks and compliance standards, such as GDPR, HIPAA, or PCI-DSS, require or strongly recommend encrypting data in transit. Enabling TLS on SQL Server helps meet these compliance standards, strengthens internal security protections, and avoids potential penalties.

Security Best Practice

Implementing TLS is considered a fundamental security best practice in network and data communication. It reduces the risk of data breaches and enhances the overall network security posture in the enterprise.

TLS and SQL Server 2022

Microsoft SQL Server 2022 includes critical new options for administrators. The “Force Encryption” and “Force Strict Encryption” flags control how encryption is enforced for client connections, but their behavior and compatibility requirements differ.

Force Encryption

When this setting is enabled, the SQL server will encrypt communication between the client and server using TLS. However, contrary to what the name of the setting implies, it is possible for the server to accept unencrypted connections in some cases. If the client does not support encryption, the connection may still succeed without encryption. Enabling Force Encryption prioritizes encryption but does not strictly enforce it, meaning older clients that do not support encryption can still connect. Administrators can use this setting to ensure backward compatibility for applications that may not support strict encryption policies. However, upgrading applications to support encryption is strongly advised.

Force Strict Encryption

This setting is subtly different than the previous setting. It also ensures that all communication between the client and the server is encrypted without exception. If a client does not support encryption, the connection will be rejected. In addition, this setting enforces enhanced security parameters for the connection, such as certificate validation, more secure TLS cipher suites, and the use of TLS 1.3* when available. Force Strict Encryption is designed for modern security compliance. It is the preferred setting and should be used when all clients are known to support encryption.

* Note: TLS 1.3 is supported with SQL Server 2022 cumulative update 1 or later installed.

Key Differences

The following table summarizes the key differences between Force Encryption and Force Strict Encryption.

Force EncryptionEncourages but does not require encryption. Unencrypted connections may still be allowed.
Force Strict EncryptionRequires encryption for all connections. Clients that do not support encryption will be rejected.

Summary

By securing your Microsoft SQL Server with TLS, you significantly enhance the security, reliability, and trustworthiness of your data management systems. In the next post, I’ll provide detailed step-by-step guidance for enabling and configuring TLS on Microsoft SQL Server 2022 using best security practices.

Additional Information

Step-by-Step Guide: Enable TLS in Microsoft SQL Server 2022

VIDEO: Enable TLS in Microsoft SQL Server 2022

Microsoft SQL Server 2022

1 Comment
by Richard M. Hicks on February 27, 2025  •  Permalink
Posted in Authentication and MFA, Certificate-Based Authentication, Cryptography, PKI, TLS, Windows Server
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Posted by Richard M. Hicks on February 27, 2025

https://directaccess.richardhicks.com/2025/02/27/tls-and-microsoft-sql-server-2022/

Microsoft Intune Cloud PKI and Certificate Templates

Microsoft recently announced the general availability of its new PKI-as-a-Service platform called Microsoft Intune Cloud PKI. With Intune Cloud PKI, administrators create certification authorities (CAs) to issue and manage user and device authentication certificates for Intune-managed endpoints. Cloud PKI also provides hosted Authority Information Access (AIA) and Certificate Revocation List (CRL) Distribution Point (CDP) services, in addition to Simple Certificate Enrollment Protocol (SCEP) service, so administrators do not have to deploy on-premises infrastructure to take advantage of certificate-based authentication.

Certificate Templates

After deploying your Intune Cloud PKI root and issuing CAs, you may wonder where to find the associated certificate templates. If you are familiar with traditional on-premises Active Directory Certificate Services (AD CS) implementations, this is how you define the purpose, key policy, security parameters, and lifetime of the certificate issued using that template. However, Intune Cloud PKI does not use certificate templates in the traditional way many administrators are familiar with.

Note: Microsoft may introduce support for certificate templates for Intune Cloud PKI in the future. However, it is not supported at the time of this writing.

SCEP Profile

Administrators define certificate policies and security parameters using Intune’s SCEP device configuration profile instead of certificate templates. In essence, the SCEP profile functions as the certificate template. With the Intune device configuration profile, administrators can define the following settings.

Certificate Type

The certificate type can be either a user or a device. Intune Cloud PKI can issue certificates for either or both, as required.

Subject Name (User)

The subject name is unimportant for user authentication certificates because the User Principal Name (UPN) defined in the Subject Alternative Name field is used to authenticate the user. In this field, the administrator can use whatever they like. However, it’s common to use the username here. Avoid using the email attribute here because there’s no guarantee that every user will have this defined on the Active Directory (AD) user object.

Subject Name (Device)

Administrators should supply the device’s fully qualified domain name (FQDN) for device authentication certificates in the subject name field. For hybrid Entra joined devices, administrators can use the {{FullyQualifiedDomainName}} variable. For native Entra-joined devices, you can use {{DeviceName}} and append your DNS suffix, for example, {{DeviceName}}.corp.example.net.

Note: Intune supports numerous variables to populate fields for certificates. You can find a list of supported variables in the following locations.

User Certificate Variables: https://learn.microsoft.com/en-us/mem/intune/protect/certificates-profile-scep#create-a-scep-certificate-profile:~:text=Manager%20blog%20post.-,User%20certificate%20type,-Use%20the%20text

Device Certificate Variables: https://learn.microsoft.com/en-us/mem/intune/protect/certificates-profile-scep#create-a-scep-certificate-profile:~:text=on%20the%20device.-,Device%20certificate%20type,-Format%20options%20for

Subject Alternative Name (User)

The Subject Alternative Name (SAN) field for user authentication certificates should be populated with the User Principal Name (UPN) value. Ensure this value is appropriately configured internally and supports sign-in to AD.

Subject Alternative Name (Device)

The SAN field for device authentication certificates should be populated with the device’s FQDN. Follow the guidance for device subject names covered previously.

Certificate Validity Period

This field allows the administrator to define the certificate’s validity period. The best practice is to limit the lifetime to no more than one year. A shorter lifetime is recommended for certificates not backed by a Trusted Platform Module (TPM).

Key Storage Provider

This value is critical to ensuring integrity for issued user and device authentication certificates. The best practice is to select Enroll to Trusted Platform Module (TPM) KSP, otherwise fail. However, if you must issue certificates to endpoints without a TPM (e.g., legacy devices, virtual machines, etc.), consider a separate profile with a shorter certificate lifetime to limit exposure.

Key Usage

Digital signature and Key encipherment are required for user and device authentication certificates.

Key Size

The 2048-bit key size is the minimum recommended value for certificates with RSA keys. Using 4096-bit is not recommended for end-entity certificates and can potentially cause conflicts in some cases. Intune Cloud PKI does not support the 1024-bit key size.

Hash Algorithm

SHA-2 is the best practice for the hash algorithm. SHA-1 has been deprecated and should not be used.

Root Certificate

Select the Cloud PKI root CA certificate.

Extended Key Usage

The minimum requirement for user and device authentication certificates is Client Authentication (1.3.6.1.5.5.7.3.2).

Renewal Threshold

This value specifies at what point the certificate can be renewed. 20% is commonly used for certificates with a one-year lifetime.

SCEP Server URLs

This value can be found on the configuration properties page of your Cloud PKI issuing CA. The URI will include a variable in the URL. The variable is there by design. Copy and paste this URL exactly as displayed in the SCEP URL field.

Training

Are you interested in learning more about issuing and managing certificates with Microsoft Intune? Would you like to know how to securely and optimally implement PKCS and SCEP infrastructure on-premises? Do you want more details about deploying and managing Microsoft Intune Cloud PKI? Register now for my upcoming three-day live Certificates and Intune Masterclass training event at the ViaMonstra online training academy. We’ll deep-dive into all aspects of certificate management using Intune with on-premises AD CS and Intune Cloud PKI. I’ll be sharing many advanced techniques for adequately securing your certificate infrastructure. Space is limited, so register now!

Additional Information

Mastering Certificates with Intune Training Course

Microsoft Intune Cloud PKI Overview

Microsoft Intune Cloud PKI and Active Directory

Microsoft Intune Certificate Connector Failure

Microsoft Intune Certificate Connector Configuration Failed

Microsoft Intune Certificate Connector Configuration Failure

Microsoft Intune Certificate Connector Service Account and PKCS

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by Richard M. Hicks on March 25, 2024  •  Permalink
Posted in Authentication and MFA, Azure and AWS, Certificate-Based Authentication, Cloud PKI, Cryptography, Entra ID, Intune Certificate Connector, Microsoft Intune, NDES and SCEP, PKI, Training and Events, Windows Server
Tagged , , , , , , , , , , , , , ,

Posted by Richard M. Hicks on March 25, 2024

https://directaccess.richardhicks.com/2024/03/25/microsoft-intune-cloud-pki-and-certificate-templates/

Always On VPN NPS and PEAP Vulnerabilities

The February 2023 security updates for Windows Server address multiple vulnerabilities that affect Microsoft Always On VPN administrators. This latest update addresses multiple critical and important vulnerabilities in the Network Policy Server (NPS), commonly used to perform RADIUS authentication for Always On VPN servers. Specifically, there are several Remote Code Execution (RCE) and Denial of Service (DoS) vulnerabilities with Protected Extensible Authentication Protocol (PEAP). PEAP with user authentication certificates is the authentication protocol of choice for Always On VPN user tunnel authentication.

Vulnerabilities

The following is a list of vulnerabilities in PEAP addressed in the February 2023 security update.

  • CVE-2023-21689 – Microsoft PEAP Remote Code Execution Vulnerability (critical)
  • CVE-2023-21690 – Microsoft PEAP Remote Code Execution Vulnerability (critical)
  • CVE-2023-21691 – Microsoft PEAP Information Disclosure vulnerability (important)
  • CVE-2023-21692 – Microsoft PEAP Remote Code Execution Vulnerability (critical)
  • CVE-2023-21695 – Microsoft PEAP Remote Code Execution Vulnerability (important)
  • CVE-2023-21701 – Microsoft PEAP Denial of Service Vulnerability (important)

Mitigation

Unauthenticated attackers can exploit the RCE vulnerabilities in PEAP on Microsoft Windows NPS servers. However, NPS servers should not be exposed directly to the Internet and would require an attacker to have access to the internal network already. However, administrators are advised to apply this update to their NPS servers as soon as possible. In addition, organizations that deploy the NPS role on enterprise domain controllers should update immediately.

Additional Information

February 2023 Update for Windows Server 2022 (KB5022842)

February 2023 Update for Windows Server 2019 (KB022840)

February 2023 Update for Windows Server 2016 (KB5022838)

2 Comments
by Richard M. Hicks on February 16, 2023  •  Permalink
Posted in Always On VPN, Authentication and MFA, Cryptography, Microsoft Intune, NPS and EAP, PKI, Security Updates, Windows Server
Tagged , , , , , , , , ,

Posted by Richard M. Hicks on February 16, 2023

https://directaccess.richardhicks.com/2023/02/16/always-on-vpn-nps-and-peap-vulnerabilities/

Always On VPN Error 13868

Troubleshooting Always On VPN Error 691 and 812 – Part 2

The Internet Key Exchange version 2 (IKEv2) VPN protocol is the protocol of choice for Microsoft Always On VPN deployments where the highest levels of security and assurance are required. However, as I’ve written about in the past, often the default IKEv2 security settings are less than desirable. Before using IKEv2 VPN in a production environment the administrator will need to update these security settings accordingly.

Connection Failure

When configuring Windows Server Routing and Remote Access Service (RRAS) or a third-party VPN appliance to support IKEv2 using custom security policies, the administrator may encounter a scenario in which a connection cannot be established due to a policy mismatch error. When the connection attempt fails, an error will be recorded in the Windows Application event log from the RasClient source with Event ID 20227. The error message states the following:

“The user [username] dialed a connection named [connection name] which has failed. The error code returned on failure is 13868.”

Always On VPN IKEv2 Policy Mismatch Error

Error Code 13868

Error code 13868 translates to ERROR_IPSEC_IKE_POLICY_MATCH. Essentially this error indicates that the IKEv2 security policy on the client did not match the configuration on the server.

Server Configuration

To view the current IKEv2 IPsec policy configuration, open an elevated PowerShell command window and run the following command.

Get-VpnServerIPsecConfiguration

Always On VPN IKEv2 Policy Mismatch Error

Client Configuration

To ensure interoperability, the VPN client must be configured to use the same IKEv2 security policy as defined on the sever. To view a VPN client’s currently configured IKEv2 security policy, open an elevated PowerShell command window and run the following command.

Get-VpnConnection -Name [connection name] | Select-Object -ExpandProperty IPsecCustomPolicy

Always On VPN IKEv2 Policy Mismatch Error

Note: If this PowerShell command returns no output, the VPN connection is not using a custom IKEv2 IPsec security policy.

Updating Settings

Guidance for configuring IKEv2 security policies on Windows Server RRAS and Windows 10 can be found here.

NPS Policy

Another common cause of IKEv2 policy mismatch errors is a misconfigured Network Policy Server (NPS) network policy. Specifically, administrators may disable Basic and Strong encryption for MPPE in an attempt to improve security.

Always On VPN IKEv2 Policy Mismatch Error

The NPS policy for Always On VPN must include Strong encryption at a minimum. Basic and No encryption can be safely disabled.

Always On VPN IKEv2 Policy Mismatch Error

Summary

IKEv2 policy mismatch errors can be resolved easily by ensuring both the VPN server and client are configured to use the same IPsec security policies. Use the PowerShell commands in the above referenced above to validate settings and make changes when necessary.

Additional Information

Microsoft Always On VPN Error 13801

Microsoft Windows Always On VPN Error 13806

Microsoft Windows Always On VPN Certificate Requirements for IKEv2

Microsoft Windows Always On VPN IPsec Root Certificate Configuration Issue

Microsoft Windows Always On VPN IKEv2 Policy Mismatch Error

Microsoft Windows Always On VPN IKEv2 Security Configuration

Microsoft Windows Always On VPN IKEv2 Fragmentation

Microsoft Windows Always On VPN IKEv2 Load Balancing and NAT

Microsoft Windows Always On VPN IKEv2 Features and Limitations

1 Comment
by Richard M. Hicks on February 12, 2023  •  Permalink
Posted in Always On VPN, Authentication and MFA, Cryptography, NPS and EAP, PKI, PowerShell, Windows Server
Tagged , , , , , , , , , , , ,

Posted by Richard M. Hicks on February 12, 2023

https://directaccess.richardhicks.com/2023/02/12/always-on-vpn-error-13868/

Always On VPN SSTP Load Balancing with Citrix NetScaler ADC

Always On VPN SSTP Load Balancing with Citrix NetScaler ADCOne of the many advantages of using Windows Server Routing and Remote Access Service (RRAS) as the VPN server to support Windows 10 Always On VPN connections is that it includes support for the Secure Socket Tunneling Protocol (SSTP). SSTP is a TLS-based VPN protocol that is easy to configure and deploy and is very firewall friendly. This ensures consistent and reliable connectivity even behind restrictive firewalls. The Citrix ADC (formerly NetScaler) is a popular platform for load balancing Always On VPN connections. In this article I’ll describe how to configure load balancing on the Citrix ADC for RRAS VPN connections using the SSTP VPN protocol.

Special Note: In December 2019 a serious security vulnerability was discovered on the Citrix ADC that gives an unauthenticated attacker the ability to arbitrarily execute code on the appliance. As of this writing a fix is not available (due end of January 2020) but a temporary workaround can be found here.

Load Balancing SSTP

Previously I’ve written about some of the use cases and benefits of SSTP load balancing as well as the options for offloading TLS for SSTP VPN connections. Load balancing SSTP eliminates single points of failure and enables support for multiple RRAS VPN servers to increase scalability. It is generally recommended that the Citrix ADC be configured to pass through encrypted SSTP VPN connections. However, TLS offloading can be configured to improve performance and reduce resource utilization on VPN servers, if required.

Configuration

Load balancing SSTP on the Citrix ADC is straightforward and not unlike load balancing a common HTTPS web server. Below are specific settings and parameters required to load balance SSTP using the Citrix ADC.

Note: This article is not a comprehensive configuration guide for the Citrix ADC. It assumes the administrator is familiar with basic load balancing concepts and has experience configuring the Citrix ADC.

Service Settings

The load balancing service for SSTP VPN should be configured to use TCP port 443 and the SSL_BRIDGE protocol. If TLS offload is required, TCP port 80 and the HTTP protocol can be configured. Additional configuration is required on the RRAS server when TLS offload is enabled, however. Detailed information for configuring RRAS and SSTP for TLS offload can be found here.

Always On VPN SSTP Load Balancing with Citrix NetScaler ADC

Virtual Server Settings

The virtual server is configured to use TCP port 443. It is recommended to use SSLSESSION persistence.

Always On VPN SSTP Load Balancing with Citrix NetScaler ADC

The LEASTCONNECTION load balancing method is the recommend option for load balancing method.

Always On VPN SSTP Load Balancing with Citrix NetScaler ADC

Service Monitoring

Using the default TCP monitor (tcp-default) is not recommended for monitoring SSTP, as a simple TCP port check does not accurately reflect the health of the SSTP service running on the RRAS server. To more precisely monitor the SSTP service status, a new custom monitor must be created and bound to the load balancing services. Follow the steps below to configure a custom SSTP VPN monitor on the Citrix ADC.

  1. Open the Citrix ADC management console and expand Traffic Management.
  2. Select Monitors.
  3. Click Add.
  4. Enter a descriptive name in the Name field.
  5. Select HTTP form the Type drop-down list and click Select.
  6. Adjust the Interval and Response Time-out values according to your requirements.
  7. Enter 401 in the Response Codes field and click the “+” button.
  8. In the Response Codes field click the “x” next to 200.
  9. In the HTTP Request field enter HEAD /sra_{BA195980-CD49-458b-9E23-C84EE0ADCD75}/.
  10. Check the box next to Secure (not required if TLS offload is enabled).
  11. Select ns_default_ssl_profile_backend from the SSL profile drop-down list (not required if TLS offload is enabled).
  12. Click Create.

Always On VPN SSTP Load Balancing with Citrix NetScaler ADC

Once complete, bind the new service monitor to the load balancing services or service groups accordingly.

TLS Offload

It is generally recommended that TLS offload not be enabled for SSTP VPN. However, if TLS offload is desired, it is configured in much the same way as a common HTTPS web server. Specific guidance for enabling TLS offload on the Citrix ADC can be found here. Details for configuring RRAS and SSTP to support TLS offload can be found here.

Certificates

When enabling TLS offload for SSTP VPN connections it is recommended that the public SSL certificate be installed on the RRAS server, even though TLS processing will be handled on the Citrix ADC and HTTP will be used between the Citrix ADC and the RRAS server. If installing the public SSL certificate on the RRAS server is not an option, additional configuration will be required. Specifically, TLS offload for SSTP must be configured using the Enable-SSTPOffload.ps1 PowerShell script, which can be found here.

Once the script has been downloaded, open an elevated PowerShell command window and enter the following command.

.\Enable-SSTPOffload.ps1 -CertificateHash [SHA256 Certificate Hash of Public SSL Certificate] -Restart

Example:

.\Enable-SSTPOffload.ps1 -CertificateHash ‘C3AB8FF13720E8AD9047DD39466B3C8974E592C2FA383D4A3960714CAEF0C4F2’ -Restart

Re-Encryption

When offloading TLS for SSTP VPN connections, all traffic between the Citrix ADC and the RRAS server will be sent in the clear using HTTP. In some instances, TLS offload is required only for traffic inspection, not performance gain. In this scenario the Citrix ADC will be configured to terminate and then re-encrypt connections to the RRAS server. When terminating TLS on the Citrix ADC and re-encrypting connections to the RRAS server is required, the same certificate must be used on both the Citrix ADC and the RRAS server. Using different certificates on the RRAS server and the load balancer is not supported.

Additional Information

Windows 10 Always On VPN Load Balancing and SSL Offload

SSL Offload Configuration for Citrix ADC (NetScaler)

Windows 10 Always On VPN SSTP Load Balancing with Kemp LoadMaster

Windows 10 Always On VPN SSTP Load Balancing with F5 BIG-IP

Windows 10 Always On VPN Connects then Disconnects

Windows 10 Always On VPN SSL Certificate Requirements for SSTP

8 Comments
by Richard M. Hicks on January 13, 2020  •  Permalink
Posted in Always On VPN, Load Balancing, PKI, TLS, Windows Server
Tagged , , , , , , , , , , , , ,

Posted by Richard M. Hicks on January 13, 2020

https://directaccess.richardhicks.com/2020/01/13/always-on-vpn-sstp-load-balancing-with-citrix-netscaler-adc/

Always On VPN SSTP Load Balancing with F5 BIG-IP

Always On VPN SSTP Load Balancing with F5 BIG-IP The Windows Server Routing and Remote Access Service (RRAS) includes support for the Secure Sockets Tunneling Protocol (SSTP), which is a Microsoft proprietary VPN protocol that uses SSL/TLS for security and privacy of VPN connections. The advantage of using SSTP for Always On VPN is that it is firewall friendly and ensures consistent remote connectivity even behind highly restrictive firewalls.

Load Balancing SSTP

In a recent post, I described some of the use cases and benefits of SSTP load balancing as well as the offloading of TLS for SSTP VPN connections. Using a load balancer for SSTP VPN connections increases scalability, and offloading TLS for SSTP reduces resource utilization and improves performance for VPN connections. There are positive security benefits too.

Configuration

Enabling load balancing for SSTP on the F5 BIG-IP load balancer is fundamentally similar to load balancing HTTPS web servers. However, there are a few subtle but important differences.

Default Monitor

The default HTTP and HTTPS monitors on the F5 will not accurately reflect the health of the SSTP service running on the RRAS server. In addition, using a simple TCP port monitor could yield unexpected results. To ensure accurate service status monitoring, a new custom monitor must be created to validate the health of the SSTP service.

Custom SSTP Monitor

Open the F5 BIG-IP management console and follow the steps below to create and assign a new custom monitor for SSTP.

Create Monitor

1. In the navigation tree highlight Local Traffic.
2. Click Monitors.
3. Click Create.

Always On VPN SSTP Load Balancing with F5 BIG-IP

4. Enter a descriptive name in the Name field and from the Type drop-down list choose HTTP if TLS offload is enabled, or HTTPS if it is not.
5. In the Send String field enter HEAD /sra_{BA195980-CD49-458b-9E23-C84EE0ADCD75}/ HTTP/1.1\r\nHost:r\nConnection: Close\r\n\r\n.
6. In the Receive String field enter HTTP/1.1 401.
7. Click Finished.

Always On VPN SSTP Load Balancing with F5 BIG-IP

Assign Monitor

1. Below Local Traffic click Pools.
2. Click on the SSTP VPN server pool.
3. In the Health Monitors section select the SSTP VPN health monitor from the Available list and make it Active.
4. Click Update.

Always On VPN SSTP Load Balancing with F5 BIG-IP

CLI Configuration

If you prefer to configure the SSTP VPN monitor using the F5’s Command Line Interface (CLI), you can download the monitor configuration from my GitHub here.

TLS Offload

It is generally recommended that TLS offload not be enabled for SSTP VPN. However, if TLS offload is desired, it is configured in much the same way as a common HTTPS web server. Specific guidance for enabling TLS offload on the F5 BIG-IP can be found here. Details for configuring RRAS and SSTP to support TLS offload can be found here.

Certificates

When enabling TLS offload for SSTP VPN connections it is recommended that the public SSL certificate be installed on the RRAS server, even though TLS processing will be handled on the F5 and HTTP will be used between the F5 and the RRAS server. If installing the public SSL certificate on the RRAS server is not an option, additional configuration will be required. Specifically, TLS offload for SSTP must be configured using the Enable-SSTPOffload PowerShell script, which can be found here.

Once the script has been downloaded, open an elevated PowerShell command window and enter the following command.

Enable-SSTPOffload -CertificateHash [SHA256 Certificate Hash of Public SSL Certificate] -Restart

Example:

Enable-SSTPOffload -CertificateHash “C3AB8FF13720E8AD9047DD39466B3C8974E592C2FA383D4A3960714CAEF0C4F2” -Restart

Re-Encryption

When offloading TLS for SSTP VPN connections, all traffic between the F5 and the RRAS server will be sent in the clear using HTTP. In some instances, TLS offload is required only for traffic inspection, not performance gain. In this scenario the F5 will be configured to terminate and then re-encrypt connections to the RRAS server. When terminating TLS on the F5 and re-encrypting connections to the RRAS server is required, the same certificate must be used on both the F5 and the RRAS server. Using different certificates on the RRAS server and the load balancer is not supported.

Additional Information

Windows 10 Always On VPN SSTP Load Balancing and SSL Offload

Windows 10 Always On VPN SSL Certificate Requirements for SSTP

Windows 10 Always On VPN ECDSA SSL Certificate Request for SSTP

Windows 10 Always On VPN SSTP Connects then Disconnects

Windows 10 Always On VPN Load Balancing Deployment Guide for Kemp Load Balancers

 

23 Comments
by Richard M. Hicks on June 17, 2019  •  Permalink
Posted in Always On VPN, Cryptography, Load Balancing, PKI, PowerShell, TLS, Windows Server
Tagged , , , , , , , , , , , , , , , , , ,

Posted by Richard M. Hicks on June 17, 2019

https://directaccess.richardhicks.com/2019/06/17/always-on-vpn-sstp-load-balancing-with-f5-big-ip/

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