Assign S/MIME certificates (.cer files) to multiple Exchange Mailboxes using Set-Mailbox cmdlet and UserSMIMECertificate parameter

Question

Hi all,

I have a CSV input file which contains a number of mailbox PrimarySMTPAddress values e.g.

PrimarySMTPAddress

******@test.com

******@test.com

******@test.com

I also have corresponding .cer (S/MIME Public certificates) stored on a file server for each mailbox i.e.

"D:\Certificates******@test.com.cer"

"D:\Certificates******@test.com.cer"

"D:\Certificates******@test.com.cer"

I have some PowerShell code which works to assign the .cer certificate to an individual mailbox using the Set-Mailbox cmdlet (see below):

$cert=New-Object System.Security.Cryptography.X509Certificates.X509Certificate2("C:\temp******@test.com.cer")

$certArray = New-Object System.Collections.ArrayList

$certArray.Insert(0,$cert.GetRawCertData())

*Set-Mailbox -Identity *****@test.com -UserSMIMECertificate $certArray

What I would like to have is a PowerShell script which will read the contents of the input.csv file (which contains the PrimarySMTPAddress values of each mailbox) and then assign (using the Set-Mailbox cmdlet and UserSMIMECertificate parameter) the .cer files to each of the related mailboxes.

Thanks in advance!

Answer 1

Something like this should work:

ForEach ($u in (Import-CSV C:\MyStuff\PrimarySMTPAddress.csv)){
    $p = Join-Path C:\Temp -ChildPath ("{0}.cer" -f $u.PrimarySMTPAddress)
    $cert=New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($p)
    $certArray = New-Object System.Collections.ArrayList
    $certArray.Insert(0,$cert.GetRawCertData())
    Set-Mailbox -Identity $u.PrimarySMTPAddress -UserSMIMECertificate $certArray
}

Adjust the path and file names accordingly.

The code's untested as I have no access to an Exchange server or any certificates.

Answer 2

Hi, @mark terry

I noticed that you are using the Exchange Online tag, please understand that Exchange Online is currently focused on Exchange and mail flow issues, not on scripts.

Based on my personal search, the following script is just for your reference:

# Define the path to the CSV file
$csvPath = "C:\path\to\input.csv"
 
# Import the CSV file
$mailboxes = Import-Csv -Path $csvPath
 
# Loop through each mailbox in the CSV file
foreach ($mailbox in $mailboxes) {
    # Get the PrimarySMTPAddress
    $primarySMTPAddress = $mailbox.PrimarySMTPAddress
 
    # Define the path to the .cer file
    $certPath = "D:\Certificates\$primarySMTPAddress.cer"
 
    # Load the certificate
    $cert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($certPath)
 
    # Create an array list and add the certificate data
    $certArray = New-Object System.Collections.ArrayList
    $certArray.Insert(0, $cert.GetRawCertData())
 
    # Assign the certificate to the mailbox
    Set-Mailbox -Identity $primarySMTPAddress -UserSMIMECertificate $certArray
}

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