ADCSTemplate.psm1

#requires -Version 5.0 -Modules ActiveDirectory

Function Get-RandomHex {
    param ([int]$Length)
        $Hex = '0123456789ABCDEF'
        [string]$Return = $null
        For ($i=1;$i -le $length;$i++) {
            $Return += $Hex.Substring((Get-Random -Minimum 0 -Maximum 16),1)
        }
        Return $Return
    }
    
    Function IsUniqueOID {
    param ($cn,$TemplateOID,$Server,$ConfigNC)
        $Search = Get-ADObject -Server $Server `
            -SearchBase "CN=OID,CN=Public Key Services,CN=Services,$ConfigNC" `
            -Filter {cn -eq $cn -and msPKI-Cert-Template-OID -eq $TemplateOID}
        If ($Search) {$False} Else {$True}
    }
    
    Function New-TemplateOID {
    Param($Server,$ConfigNC)
        <#
        OID CN/Name                                                         [10000000-99999999].[32 hex characters (MD5hash)]
        OID msPKI-Cert-Template-OID    [Forest base OID].[1000000-99999999].[10000000-99999999]  <--- second number same as first number in OID name
        #>
        do {
            $OID_Part_1 = Get-Random -Minimum 10000000 -Maximum 99999999
            $OID_Part_2 = Get-Random -Minimum 10000000 -Maximum 99999999
            $OID_Part_3 = Get-RandomHex -Length 32
            $OID_Forest = Get-ADObject -Server $Server `
                -Identity "CN=OID,CN=Public Key Services,CN=Services,$ConfigNC" `
                -Properties msPKI-Cert-Template-OID |
                Select-Object -ExpandProperty msPKI-Cert-Template-OID
            $msPKICertTemplateOID = "$OID_Forest.$OID_Part_1.$OID_Part_2"
            $Name = "$OID_Part_2.$OID_Part_3"
        } until (IsUniqueOID -cn $Name -TemplateOID $msPKICertTemplateOID -Server $Server -ConfigNC $ConfigNC)
        Return @{
            TemplateOID  = $msPKICertTemplateOID
            TemplateName = $Name
        }
    }
    
    
    <#
    .SYNOPSIS
    Returns the properties of either a single or all Active Directory Certificate Template(s).
    .DESCRIPTION
    Returns the properties of either a single or list of Active Directory Certificate Template(s)
    depending on whether a DisplayName parameter was passed.
    .PARAMETER DisplayName
    Name of an AD CS template to retrieve.
    .PARAMETER Server
    FQDN of Active Directory Domain Controller to target for the operation.
    When not specified it will search for the nearest Domain Controller.
    .EXAMPLE
    PS C:\> Get-ADCSTemplate
    .EXAMPLE
    PS C:\> Get-ADCSTemplate -DisplayName PowerShellCMS
    .EXAMPLE
    PS C:\> Get-ADCSTemplate | Sort-Object Name | ft Name, Created, Modified
    .EXAMPLE
    PS C:\> ###View template permissions
    (Get-ADCSTemplate pscms).nTSecurityDescriptor
    (Get-ADCSTemplate pscms).nTSecurityDescriptor.Sddl
    (Get-ADCSTemplate pscms).nTSecurityDescriptor.Access
    ConvertFrom-SddlString -Sddl (Get-ADCSTemplate pscms).nTSecurityDescriptor.sddl -Type ActiveDirectoryRights
    .NOTES
    Requires Enterprise Administrator permissions, since this touches the AD Configuration partition.
    #>
    Function Get-ADCSTemplate {
    param(
        [parameter(Position=0)]
        [string]
        $DisplayName,
    
        [string]
        $Server = (Get-ADDomainController -Discover -ForceDiscover -Writable).HostName[0]
    )
        If ($PSBoundParameters.ContainsKey('DisplayName')) {
            $LDAPFilter = "(&(objectClass=pKICertificateTemplate)(displayName=$DisplayName))"
        } Else {
            $LDAPFilter = '(objectClass=pKICertificateTemplate)'
        }
    
        $ConfigNC     = $((Get-ADRootDSE -Server $Server).configurationNamingContext)
        $TemplatePath = "CN=Certificate Templates,CN=Public Key Services,CN=Services,$ConfigNC"
        Get-ADObject -SearchScope Subtree -SearchBase $TemplatePath -LDAPFilter $LDAPFilter -Properties * -Server $Server
    }
    
    
    <#
    .SYNOPSIS
    Adds an ACL to an Active Directory Certificate template.
    .DESCRIPTION
    Adds an ACL to an Active Directory Certificate template.
    Default permission is read (without the Enroll or AutoEnroll switches).
    .PARAMETER DisplayName
    Name of an AD CS template to receive the ACL.
    .PARAMETER Server
    FQDN of Active Directory Domain Controller to target for the operation.
    When not specified it will search for the nearest Domain Controller.
    .PARAMETER Type
    ACL type: Allow or Deny
    .PARAMETER Identity
    String or string array of Active Directory identities (users or groups)
    .PARAMETER Enroll
    Set the Enroll permission
    .PARAMETER AutoEnroll
    Set the AutoEnroll permission
    .EXAMPLE
    PS C:\> Set-ADCSTemplateACL -DisplayName PowerShellCMS -Type Allow -Identity 'CONTOSO\Servers Group' -Enroll
    .EXAMPLE
    PS C:\> Set-ADCSTemplateACL -DisplayName PowerShellCMS -Type Allow -Identity 'CONTOSO\Servers Group','CONTOSO\Workstations Group' -Enroll -AutoEnroll
    .EXAMPLE
    PS C:\> Set-ADCSTemplateACL -DisplayName PowerShellCMS -Type Deny -Identity 'CONTOSO\Servers Group'
    .NOTES
    Requires Enterprise Administrator permissions, since this touches the AD Configuration partition.
    #>
    Function Set-ADCSTemplateACL {
    param(
        [parameter(Mandatory)]
        [string]$DisplayName,
        [string]$Server = (Get-ADDomainController -Discover -ForceDiscover -Writable).HostName[0],
        [ValidateSet('Allow','Deny')]
        [string]$Type = 'Allow',
        [string[]]$Identity,
        [switch]$Enroll,
        [switch]$AutoEnroll
    )
        ## Potential issue here that the AD: drive may not be targetting the selected DC in the -SERVER parameter
        $TemplatePath        = "AD:\" + (Get-ADCSTemplate -DisplayName $DisplayName -Server $Server).DistinguishedName
        $acl                 = Get-ACL $TemplatePath
        $InheritedObjectType = [GUID]'00000000-0000-0000-0000-000000000000'
        ForEach ($Group in $Identity) {
            $account = New-Object System.Security.Principal.NTAccount($Group)
            $sid     = $account.Translate([System.Security.Principal.SecurityIdentifier])
    
            If ($Type -ne 'Deny') {
                # Read, but only if Allow
                $ObjectType = [GUID]'00000000-0000-0000-0000-000000000000'
                $ace        = New-Object System.DirectoryServices.ActiveDirectoryAccessRule `
                    $sid, 'GenericRead', $Type, $ObjectType, 'None', $InheritedObjectType
                $acl.AddAccessRule($ace)
            }
    
            If ($Enroll) {
                $ObjectType = [GUID]'0e10c968-78fb-11d2-90d4-00c04f79dc55'
                $ace        = New-Object System.DirectoryServices.ActiveDirectoryAccessRule `
                    $sid, 'ExtendedRight', $Type, $ObjectType, 'None', $InheritedObjectType
                $acl.AddAccessRule($ace)
            }
    
            If ($AutoEnroll) {
                $ObjectType = [GUID]'a05b8cc2-17bc-4802-a710-e7c15ab866a2'
                $ace        = New-Object System.DirectoryServices.ActiveDirectoryAccessRule `
                    $sid, 'ExtendedRight', $Type, $ObjectType, 'None', $InheritedObjectType
                $acl.AddAccessRule($ace)
            }
        }
        Set-ACL $TemplatePath -AclObject $acl
    }
    
    
    <#
    .SYNOPSIS
    Returns a JSON string with the properties of an Active Directory certificate template.
    .DESCRIPTION
    Returns a JSON string with the properties of an Active Directory certificate template.
    By default returns only the PKI-related properties of the object. These properties are
    sufficient for passing to the New-ADCSTemplate function.
    .PARAMETER DisplayName
    DisplayName for the certificate to export.
    .PARAMETER Server
    FQDN of Active Directory Domain Controller to target for the operation.
    When not specified it will search for the nearest Domain Controller.
    .PARAMETER Detailed
    Includes all ADObject properties of the template. These are not required for 
    use with the New-ADCSTemplate function.
    .NOTES
    C.R.U.D. AD CS Template Operations in this module.
    No longer have to use the cert GUI to clone a template and build a new one.
    Create one manually the first time in the GUI, then export it to JSON.
    Pass the JSON in your new environment (file, here string, DSC, etc.) to build from scratch.
    Requires Enterprise Administrator permissions, since this touches the AD Configuration partition.
    .EXAMPLE
    PS C:\> Export-ADCSTemplate -DisplayName PowerShellCMS
    .EXAMPLE
    PS C:\> Export-ADCSTemplate -DisplayName PowerShellCMS -Detailed
    .EXAMPLE
    ### Backup all the templates to JSON
    md C:\ADCSTemplates -ErrorAction SilentlyContinue
    cd C:\ADCSTemplates
    (Get-ADCSTemplate).name | ForEach-Object {"Exporting $_"; Export-ADCSTemplate -DisplayName $_ | Out-File .\$_.json -Force}
    dir
    .EXAMPLE
    PS C:\> New-ADCSTemplate -DisplayName PowerShellCMS-NEW -JSON (Export-ADCSTemplate -DisplayName PowerShellCMS-OLD)
    #>
    Function Export-ADCSTemplate {
    param(
        [parameter(Mandatory)]
        [string]$DisplayName,
        [string]$Server = (Get-ADDomainController -Discover -ForceDiscover -Writable).HostName[0],
        [switch]$Detailed   # Detailed output is not required for export/import. Use for documentation/backup purposes.
    )
        If ($Detailed) {
            Get-ADCSTemplate -DisplayName $DisplayName -Server $Server |
                ConvertTo-Json
        } Else {
            Get-ADCSTemplate -DisplayName $DisplayName -Server $Server |
                Select-Object -Property name, displayName, objectClass, flags, revision, *pki* |
                ConvertTo-Json
        }
    }
    
    <#
    .SYNOPSIS
    Creates a new Active Directory Certificate Services template based on a JSON export.
    .DESCRIPTION
    Creates a new Active Directory Certificate Services template based on a JSON export.
    Optionally can permission and publish the template (best practice).
    .PARAMETER DisplayName
    DisplayName for the certificate template to create. This does not have to match
    the original name of the exported template.
    .PARAMETER JSON
    JSON string output from Export-ADCSTemplate. Defines the template to create.
    Can be retrieved from file using Get-Content -Raw.
    .PARAMETER Server
    FQDN of Active Directory Domain Controller to target for the operation.
    When not specified it will search for the nearest Domain Controller.
    .PARAMETER Identity
    String or string array of Active Directory identities (users or groups).
    This is optional for permissioning the template.
    .PARAMETER AutoEnroll
    Default permission is Read and Enroll. Use this switch to also grant AutoEnroll 
    to the identity. Only used when Identity parameter is used.
    .PARAMETER Publish
    Publish the template to *ALL* Certificate Authority issuers. Use with caution
    in production environments. You may want to manually publish to only specific
    Certificate Authorities in production. In a lab this is ideal.
    .NOTES
    This function does not use the official (complicated) API for PKI management.
    Instead it creates the exact same AD objects that are generated by the API,
    including AD forest-specific OIDs.
    Requires Enterprise Administrator permissions, since this touches the AD Configuration partition.
    .EXAMPLE
    PS C:\> New-ADCSTemplate -DisplayName PowerShellCMS -JSON (Get-Content .\pscms.json -Raw)
    .EXAMPLE
    PS C:\> New-ADCSTemplate -DisplayName PowerShellCMS -JSON (Get-Content .\pscms.json -Raw) -Server dc1.contoso.com -Identity G_DSCNodes -AutoEnroll -Publish
    
    # From a client configured for AD CS autoenrollment:
    $Req = @{
        Template          = 'PowerShellCMS'
        Url               = 'ldap:'
        CertStoreLocation = 'Cert:\LocalMachine\My'
    }
    Get-Certificate @Req
    # Note: If you have the Carbon module installed, it conflicts with Get-Certificate native cmdlet.
    
    $DocEncrCert = (dir Cert:\LocalMachine\My -DocumentEncryptionCert | Sort-Object NotBefore)[-1]
    Protect-CmsMessage -To $DocEncrCert -Content "Encrypted with my new cert from the new template!"
    .EXAMPLE
    PS C:\> New-ADCSTemplate -DisplayName PowerShellCMS-NEW -JSON (Export-ADCSTemplate -DisplayName PowerShellCMS-OLD)
    #>
    Function New-ADCSTemplate {
    param(
        [parameter(Mandatory)]
        [string]$DisplayName,   # name in JSON export is ignored
        [parameter(Mandatory)]
        [string]$JSON,
        [string]$Server = (Get-ADDomainController -Discover -ForceDiscover -Writable).HostName[0],
        [string[]]$Identity, # = "$((Get-ADDomain).NetBIOSName)\Domain Computers",
        [switch]$AutoEnroll,
        [switch]$Publish
    )
        ### Put GroupName and AutoEnroll into a parameter set
    
        # Manually import AD module to get AD: drive used later for permissions
        Import-Module ActiveDirectory -Verbose:$false
    
        $ConfigNC = $((Get-ADRootDSE -Server $Server).configurationNamingContext)
    
        #region CREATE OID
        <#
        CN                              : 14891906.F2AC4390685318BD1D950A66EDB50FF4
        DisplayName                     : TemplateNameHere
        DistinguishedName               : CN=14891906.F2AC4390685318BD1D950A66EDB50FF4,CN=OID,CN=Public Key Services,CN=Services,CN=Configuration,DC=contoso,DC=com
        dSCorePropagationData           : {1/1/1601 12:00:00 AM}
        flags                           : 1
        instanceType                    : 4
        msPKI-Cert-Template-OID         : 1.3.6.1.4.1.311.21.8.11489019.14294623.5588661.594850.12204198.151.6616009.14891906
        Name                            : 14891906.F2AC4390685318BD1D950A66EDB50FF4
        ObjectCategory                  : CN=ms-PKI-Enterprise-Oid,CN=Schema,CN=Configuration,DC=contoso,DC=com
        ObjectClass                     : msPKI-Enterprise-Oid
        #>
        $OID = New-TemplateOID -Server $Server -ConfigNC $ConfigNC
        $TemplateOIDPath = "CN=OID,CN=Public Key Services,CN=Services,$ConfigNC"
        $oa = @{
            'DisplayName' = $DisplayName
            'flags' = [System.Int32]'1'
            'msPKI-Cert-Template-OID' = $OID.TemplateOID
        }
        New-ADObject -Path $TemplateOIDPath -OtherAttributes $oa -Name $OID.TemplateName -Type 'msPKI-Enterprise-Oid' -Server $Server
        #endregion
    
        #region CREATE TEMPLATE
        # https://docs.microsoft.com/en-us/powershell/dsc/securemof#certificate-requirements
        # https://blogs.technet.microsoft.com/option_explicit/2012/04/09/pki-certificates-and-the-x-509-standard/
        # https://technet.microsoft.com/en-us/library/cc776447(v=ws.10).aspx
        $import = $JSON | ConvertFrom-Json
        $oa = @{ 'msPKI-Cert-Template-OID' = $OID.TemplateOID }
        ForEach ($prop in ($import | Get-Member -MemberType NoteProperty)) {
            Switch ($prop.Name) {
                { $_ -in 'flags',
                        'msPKI-Certificate-Name-Flag',
                        'msPKI-Enrollment-Flag',
                        'msPKI-Minimal-Key-Size',
                        'msPKI-Private-Key-Flag',
                        'msPKI-Template-Minor-Revision',
                        'msPKI-Template-Schema-Version',
                        'msPKI-RA-Signature',
                        'pKIMaxIssuingDepth',
                        'pKIDefaultKeySpec',
                        'revision'
                } { $oa.Add($_,[System.Int32]$import.$_); break }
    
                { $_ -in 'msPKI-Certificate-Application-Policy',
                        'msPKI-RA-Application-Policies',
                        'pKICriticalExtensions',
                        'pKIDefaultCSPs',
                        'pKIExtendedKeyUsage'
                } { $oa.Add($_,[Microsoft.ActiveDirectory.Management.ADPropertyValueCollection]$import.$_); break }
    
                { $_ -in 'msPKI-Supersede-Templates'
                } { $oa.Add($_,[Microsoft.ActiveDirectory.Management.ADPropertyValueCollection[]]$import.$_); break }
    
                { $_ -in 'pKIExpirationPeriod',
                        'pKIKeyUsage',
                        'pKIOverlapPeriod'
                } { $oa.Add($_,[System.Byte[]]$import.$_); break }
    
            }
        }
        $TemplatePath = "CN=Certificate Templates,CN=Public Key Services,CN=Services,$ConfigNC"
        New-ADObject -Path $TemplatePath -OtherAttributes $oa -Name $DisplayName.Replace(' ','') `
            -DisplayName $DisplayName -Type pKICertificateTemplate -Server $Server
        #endregion
    
        #region PERMISSIONS
        ## Potential issue here that the AD: drive may not be targetting the selected DC in the -SERVER parameter
        If ($PSBoundParameters.ContainsKey('Identity')) {
            If ($AutoEnroll) {
                Set-ADCSTemplateACL -DisplayName $DisplayName -Server $Server -Type Allow -Identity $Identity -Enroll -AutoEnroll
            } Else {
                Set-ADCSTemplateACL -DisplayName $DisplayName -Server $Server -Type Allow -Identity $Identity -Enroll
            }
        }
        #endregion
    
        #region ISSUE
        If ($Publish) {
            ### WARNING: Issues on all available CAs. Test in your environment.
            $EnrollmentPath = "CN=Enrollment Services,CN=Public Key Services,CN=Services,$ConfigNC"
            $CAs = Get-ADObject -SearchBase $EnrollmentPath -SearchScope OneLevel -Filter * -Server $Server
            ForEach ($CA in $CAs) {
                Set-ADObject -Identity $CA.DistinguishedName -Add @{certificateTemplates=$DisplayName.Replace(' ','')} -Server $Server
            }
        }
        #endregion
    }
    
    
    <#
    .SYNOPSIS
    Removes a certificate template from Active Directory.
    .DESCRIPTION
    Removes the template from any issuers where it is published.
    Removes the template itself.
    Removes the unique OID object of the template.
    .PARAMETER DisplayName
    DisplayName for the certificate template to delete.
    .PARAMETER Server
    FQDN of Active Directory Domain Controller to target for the operation.
    When not specified it will search for the nearest Domain Controller.
    .EXAMPLE
    PS C:\> Remove-ADCSTemplate -DisplayName PowerShellCMS
    .EXAMPLE
    PS C:\> (Get-ADCSTemplate).name | Where-Object {$_ -like "PowerShellCMS*"} | ForEach-Object {Remove-ADCSTemplate -DisplayName $_ -Verbose}
    .NOTES
    Use with caution!
    Requires Enterprise Administrator permissions, since this touches the AD Configuration partition.
    #>
    Function Remove-ADCSTemplate {
    [CmdletBinding(SupportsShouldProcess=$true,ConfirmImpact='High')]
    param(
        [parameter(Mandatory)]
        [string]$DisplayName,
        [string]$Server = (Get-ADDomainController -Discover -ForceDiscover -Writable).HostName[0]
    )
        if ($pscmdlet.ShouldProcess($DisplayName, 'Remove certificate template')) {
            $ConfigNC = $((Get-ADRootDSE -Server $Server).configurationNamingContext)
    
            $Template = Get-ADCSTemplate -DisplayName $DisplayName -Server $Server
    
            #region REMOVE ISSUE IF IT EXISTS
            $EnrollmentPath = "CN=Enrollment Services,CN=Public Key Services,CN=Services,$ConfigNC"
            $CAs = Get-ADObject -SearchBase $EnrollmentPath -SearchScope OneLevel -Filter * -Server $Server
            ForEach ($CA in $CAs) {
                Set-ADObject -Identity $CA.DistinguishedName -Remove @{certificateTemplates=$Template.cn} -Server $Server -Confirm:$false
            }
            #endregion
    
            #region REMOVE TEMPLATE
            Remove-ADObject -Identity $Template.distinguishedName -Server $Server -Confirm:$false
            #endregion
    
            #region REMOVE OID
            $TemplateOIDPath = "CN=OID,CN=Public Key Services,CN=Services,$ConfigNC"
            Get-ADObject -SearchBase $TemplateOIDPath -LDAPFilter "(DisplayName=$DisplayName)" -Server $Server | Remove-ADObject -Confirm:$false
            #endregion
        }
    }
    
    
    <#
    .SYNOPSIS
    Maps a PowerShell drive to the Active Directory Certificate Services location.
    .DESCRIPTION
    Maps a PowerShell drive to the Active Directory Certificate Services location 
    of the Configuration partition under CN=Public Key Services,CN=Services,... .
    The new drive is ADCS:. This is purely for convenience of checking the objects
    updated by functions in the ADCSTemplate module.
    .PARAMETER Server
    FQDN of Active Directory Domain Controller to target for the operation.
    When not specified it will search for the nearest Domain Controller.
    .EXAMPLE
    PS C:\> New-ADCSDrive
    PS C:\> Set-Location ADCS:
    .EXAMPLE
    ### Explore templates with drive
    New-ADCSDrive
    Get-PSDrive
    cd ADCS:
    dir
    
    # List templates
    cd '.\CN=Certificate Templates'
    dir
    dir | fl *
    dir *WebServer*
    
    # list CAs
    cd \
    cd '.\CN=Enrollment Services'
    dir
    cd C:
    .NOTES
    Requires Enterprise Administrator permissions, since this touches the AD Configuration partition.
    #>
    Function New-ADCSDrive {
    param(
        [string]$Server = (Get-ADDomainController -Discover -ForceDiscover -Writable).HostName[0]
    )
        $ConfigNC     = $((Get-ADRootDSE -Server $Server).configurationNamingContext)
        New-PSDrive -Name ADCS -PSProvider ActiveDirectory -Root "CN=Public Key Services,CN=Services,$ConfigNC" -Server $Server -Scope Global
    }
    
    
    Export-ModuleMember -Function *-ADCS*