Export-MachineCert

Export-MachineCert.ps1

Function Export-MachineCert {
<#
.SYNOPSIS
Harvests a certificate from a remote system.
.DESCRIPTION
Invokes a command on a remote system to copy the certificate to the machine running the command.
.PARAMETER Computername
Specifies the name of the remote system to harvest the certificate.
.PARAMETER Path
Provides the path where the certificate is copied to on the host system.
.PARAMETER Template
Specifies the template used when generating the certificate on the remote system.
.EXAMPLE
Export-MachineCert -computername S3 -Path C:\Certs
.Notes
Requires PowerShell version 4
Original Author:Jeff Hicks
Editor: Josh Duffney
#>
[cmdletbinding()]
Param(
[ValidateNotNullorEmpty()]
[string]$computername,
[ValidateScript({Test-Path $_})]
[string]$Path="$env:SystemDrive\Certs",
[ValidateSet("Client Authentication","Server Authentication")] 
[string]$Template


)

Try {
    #assumes a single certificate so sort on NotAfter
    Write-Verbose "Querying $computername for Machine certificates"
    $cert = invoke-command { 
     Param($template)
     Get-ChildItem Cert:\LocalMachine\my | 
     Where-Object {$_.EnhancedKeyUsageList.FriendlyName -contains $Template -AND $_.notAfter -gt (Get-Date) } |
     Sort-Object NotAfter -Descending | Select -first 1
     Write-Host $Template
     } -computername $computername -ErrorAction Stop -ArgumentList $Template
     write-verbose ($cert | out-string)
}
Catch {
    Throw $_
}

if ($cert) {

   #verify and export
   if (Test-Certificate $cert) {
    
    $exportPath  = Join-path -Path $Path -ChildPath "$computername.cer"
    Write-Verbose "Exporting certificate for $($cert.subject.trim()) to $exportpath"
    [pscustomobject]@{
     Computername = $cert.Subject.Substring(3)
     Thumbprint = $cert.Thumbprint
     Path = Export-Certificate -Cert $cert -FilePath $exportPath
    }
    
    } #if Test OK $cert
else {
        Write-Warning "Failed to verify or find a certificate"
 }
} #if $cert
} #Export-MachineCert