Enterprise Mobility : In the land of NDES – Where one eye is King and you need to watch your CRL Delta files

7:26 pm in 1702, certificates, CM12 R2 SP1, ConfigMgr 2012 R2 SP1, ConfigMgr CB, Configmgr Current Branch, CRL, EMS, Enterprise Mobility Suite, error 500, intune, Intune Standalone, ndes, NDES Connector, Windows Intune, Windws Intune by Kenny Buntinx [MVP]

I was doing a EMS POC and deployment of certificates on mobile devices was a requirement. So I needed to setup an NDES server with a separate Subordinate CA for MDM , NDES Server and SCCM Certificate Registration Point (CRP). Big deal I thought as I did it a already multiple times. At my customer we worked close with the server team and setup the infrastructure which was working fine at first sight.

After a reboot of the NDES server I was struggling to get the Network Device Enrollment Service (NDES) up and running again as it would throw me an error 500.

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The event log of the NDES Server told me the following:

The Network Device Enrollment Service cannot retrieve one of its required certificates (0x80070057). The parameter is incorrect.
The Network Device Enrollment Service cannot be started (0x80070057). The parameter is incorrect.

When the service starts, it searches for two certificates that are used by the service :

1. The service searches in the machine MY store AND

2. The certificate must have the following extensions AND

For the Key Exchange certificate:

– ExtendedKeyUsage: “Certificate Request Agent”

– KeyUsage: Encryption (0x20)

For the enrollment agent certificate:

– ExtendedKeyUsage: “Certificate Request Agent”

– KeyUsage: Signature (0x80) 

3. The certificate must not be archived AND

4. The computer must have the private key for the certificate AND

5. The certificate must be issued by the same CA that the service is configured for AND

6. The certificate must have a valid chain AND

7. If there is more than one certificate for either of the certificates that meets the previous criteria, the service will select the most recent one (the latest that was issued)

Troubleshooting certificate issues will require you to enable the CryptoAPI 2.0 Event Logging :

The CryptoAPI 2.0 Diagnostics is a feature available from Windows Server 2008 that supports the trouble shooting of issues concerned with:

– Certificate Chain Validation

– Certificate Store Operations

– Signature Verification

Enable CAPI2 logging by opening the Event Viewer and navigating to the Event Viewer (Local)\Applications and Services Logs\Microsoft\Windows\CAPI2 directory and expand it.  You should see a view named Operational.Next, right-click on the Operational view and click the Enable Log menu item.

Searching the right information under the capi2 operational log :

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I was quite sure, that I was able to download the CRL (Certificate Revocation List) and I double checked that by browsing to the URL ‘.crl”>http://pki.xxx.be/CertEnroll/<NameOfYourSubCA>.crl’ and I was able to download the file. When digging deeper in the eventID’s , I found at EventID 42 , the following URL ‘.crl”>http://pki.xxx.be/CertEnroll/<NameOfYourSubCA+>.crl’ was shown. This means it was looking for the  availability of the Delta CRL, which was visible on the web site of my CRL:

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When I finally tried to download this CRL Delta file, it failed. I remembered myself, that IIS is treating the + sign very differently in URL’s.

I needed to set the setting “Allow double escaping” in the web.config file as shown below :

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After enabling this, NDES was able to retrieve the Delta CRL file and start the service gracefully.

So if your NDES Server is throwing “The Network Device Enrollment Service cannot retrieve one of its required certificates (0x80070057). The parameter is incorrect.”, do not only check your certificates on the Server, check also your CRLs and Delta CRLs!

Hope it Helps,

Kenny Buntinx

MVP Enterprise Mobility

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