Generating wildcard certificate from internal certificate authority using PowerShell


Updated on June 24th 2017: Correction to issue where the server it was running on already has a server authentication certificate. Thank you Eric (@XenAppBlog) for the feedback.

Updated on June 25th 2017: Updated with a new version of the script that requires Windows 10 or Server 2016. The updated version adds support for password protection of the PFX file and it also cleans up private keys after export.

Hi all,

When you are building Citrix environments or any other environment that uses certificates it is often easiest to use a wildcard certificate from your internal PKI infrastructure when you are testing. I had a talk with Dave Brett at Synergy about automating the process of getting a wildcard PFX certificate that can be used during automation of Citrix installations. I thought it would be an easy task since Microsoft has baking in PowerShell in most of their products and services now, but it turned out that I couldn’t find any native PowerShell commands that allowed be to perform the task.

Since I like doing PowerShell scripts an automation that of course wasn’t the end of it, so I started digging into what can be done and I found this script on the Microsoft Script Center: MS Script Center The problem I had with this script is that I wouldn’t do wildcard certificates.

After a while I started to build my own script from scratch, but of course getting a lot of inspiration from the script found on MS Script center. I build the script out so that I would locate the CA inside the domain by itself (only tested when there is one CA in the environment) and the doing an export to a file server as well.

The script needs to be run as a domain user, so that cause a lot of testing when incorporating it with Microsoft MDT, but got that working in the end.

To use the script in MDT follow these steps:

  1. Add a “Run Command Line” action to the task sequence Skærmbillede 2017-06-07 kl. 20.49.56.png
  2. Mark “Run this step as the following account” and enter a domain user name and password as shown below Skærmbillede 2017-06-07 kl. 20.50.17.png
  3. Place the scripts in the scripts folder (or any other place you feel like and can reference) Skærmbillede 2017-06-07 kl. 20.50.46.png
  4. Edit the “New-WildcardCertificate.cmd” file to map the network drive of your choice and execute the PowerShell script. If you follow my guide it will map to your MDT deployment share. Skærmbillede 2017-06-07 kl. 20.51.26.png
  5. Run the task sequence and test it out.

The PowerShell script is shown in the bottom of this post and as always let me know if you have input or questions about it.

You can download the two scripts and ini file here: Download


For Windows 10 and 2016 only:


1 thought on “Generating wildcard certificate from internal certificate authority using PowerShell”

  1. hi martin:
    here a sample of a ssl.ini file when you want use a SAN Certificate:

    Signature=”$Windows NT$”

    Subject = “,OU=IT,O=yourcompany,L=yourlocation,S=yourstate,C=yourcountry”
    ; For a wildcard use “CN=*.CONTOSO.COM” for example
    ; For an empty subject use the following line instead or remove the Subject line entierely
    ; Subject =
    Exportable = TRUE ; Private key is not exportable
    KeyLength = 4096 ; Common key sizes: 512, 1024, 2048, 4096, 8192, 16384
    KeySpec = 1 ; AT_KEYEXCHANGE
    KeyUsage = 0xA0 ; Digital Signature, Key Encipherment
    MachineKeySet = True ; The key belongs to the local computer account
    ProviderName = “Microsoft Enhanced RSA and AES Cryptographic Provider”
    ProviderType = 12
    RequestType = PKCS10

    ; At least certreq.exe shipping with Windows Vista/Server 2008 is required to interpret the [Strings] and [Extensions] sections below


    CertificateTemplate= WebServerSAN5Years

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.