Mobile Device Management (MDM)

Automatically add the Security Identifier (SID) certificate extension to certificates requested via Mobile Device Management (MDM) - with the TameMyCerts Policy Module for Microsoft Active Directory Certificate Services (ADCS)

After several postponements, Microsoft finally decided that the Changes to Certificate Issuance and Certificate-Based Logon to Active Directory with the May 10, 2022 Patch for Windows Server (KB5014754) should now finally come into force.

Domain controllers will therefore automatically switch to full enforcement mode on February 25, 2025, unless configured otherwise. As of September 2025, it has been announced that deviating settings will no longer apply and there will therefore no longer be an alternative to full enforcement.

The consequence of this is that logins via PKInit can only be used for a login if they have the new Security Identifier (SID) certificate extension introduced with the patch.

What at first sounds as if this is not a major problem may well become one when you consider that fewer and fewer certificate-based use cases are using classic autoenrollment these days.

How the TameMyCerts Policy Module for the Active Directory Certificate Services can help with this problem is explained in more detail in the following article.

How the TameMyCerts Policy Module for Active Directory Certificate Services (ADCS) can help secure scenarios with Microsoft Intune and other Mobile Device Management (MDM) systems

Companies use Mobile Device Management (MDM) Products for managing, configuring and updating mobile devices such as smartphones, tablet computers or desktop systems via the Internet (over-the-air, OTA).

Common mobile device management products are:

Microsoft Intune
VMware Workspace One (previously known under the brand name AirWatch)
Ivanti MobileIron UEM
Jamf Pro
Baramundi Enterprise Mobility Management
BlackBerry Enterprise Mobility Suite
Sophos Mobile Control
SOTI MobiControl
Samsung Knox

Requesting certificates for endpoints managed with Microsoft Intune

In a networked world, it has become standard to work from anywhere, and also to work with mobile end devices such as smartphones or tablets in addition to classic desktop computers. Such end devices are usually connected by means of Mobile Device Management (MDM) managed by systems such as Microsoft Intune.

In most cases, users of mobile devices need digital certificates to prove their identity in order to gain access to corporate resources. Thus, it is necessary to provide these devices with an automatable yet secure interface for applying for these certificates.

Transferring S/MIME certificates to Microsoft Intune

In a modern networked world, the confidential transmission of messages in the corporate environment is essential for business success. Despite their Age it is still impossible to imagine modern corporate communications without e-mail. However, its use has changed significantly over the decades.

Nowadays, it is common to be able to read and write business e-mails on mobile devices such as smartphones and tablets. Such end devices are usually connected by means of Mobile Device Management (MDM) managed by systems such as Microsoft Intune.

For the encryption of e-mail messages, companies usually use the Secure / Multipurpose Internet Message Extensions (S/MIME) standard and provide their users with the corresponding certificates. How do these certificates get to the end devices of the users in a scalable way?

The Certificate Connector for Microsoft Intune throws the error message "ArgumentException: String cannot be of zero length" during configuration.

Assume the following scenario:

An NDES server has been set up for use with Microsoft Intune.
The configuration of the Intune Certificate Connector cannot be completed because the following error message is thrown:

Fehler bei der Microsoft Intune Certificate Connector Konfiguration. Es wurden keine Änderungen an Feature- oder Proxyeinstellungen vorgenommen.
Unerwarteter Fehler: System.ArgumentException: Die Zeichenfolge kann keine Länge von 0 (null) haben.
Parametername: name
  bei System.Security.Principal.NTAccount.ctor(String name)

Changes to Certificate Issuance and Certificate-Based Logon to Active Directory with the May 10, 2022 Patch for Windows Server (KB5014754)

With the May 10, 2022 patch, Microsoft is attempting to patch a vulnerability in the Active Directory in which the certificate-based enrollment (commonly known as PKINIT or also Smartcard Logon) to close.

The update changes both the behavior of the Certification Authority as well as the behavior of Active Directory when processing certificate-based logins.

S/MIME with the Outlook app for Apple IOS and Android only possible with devices managed via Intune

If you want to make S/MIME certificates available to your users on the smartphone as well, you may be surprised to discover that this is not possible with the Outlook app unless you also use Microsoft Intune as a management solution for the devices.

Microsoft has published in an article "Sensitivity labeling and protection in Outlook for iOS and Android" now clarified that this is due to the respective system architecture.

Network Device Enrollment Service (NDES) Basics

The Simple Certificate Enrollment Protocol (SCEP) was developed by Verisign for Cisco in the early 2000s to provide a simplified method for requesting certificates. Previously, network devices required manually generating a certificate request on each device, submitting it to a certificate authority, and then manually reinstalling the issued certificate on the corresponding device.

Certificate request fails with error message "Error Parsing Request The request subject name is invalid or too long. 0x80094001 (-2146877439 CERTSRV_E_BAD_REQUESTSUBJECT)".

Assume the following scenario

A certificate request is sent to a certification authority.
The certificate request fails with the following error message:

Error Parsing Request The request subject name is invalid or too long. 0x80094001 (-2146877439 CERTSRV_E_BAD_REQUESTSUBJECT)