windows-itpro-docs/windows/client-management/mdm/eap-configuration.md

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EAP configuration	The topic provides a step-by-step guide for creating an Extensible Authentication Protocol (EAP) configuration XML for the VPN profile and information about EAP certificate filtering in Windows 10.	DD3F2292-4B4C-4430-A57F-922FED2A8FAE		dansimp	dansimp	article	w10	windows	manikadhiman	06/26/2017

EAP configuration

The topic provides a step-by-step guide for creating an Extensible Authentication Protocol (EAP) configuration XML for the VPN profile and information about EAP certificate filtering in Windows 10.

Create an Extensible Authentication Protocol (EAP) configuration XML for the VPN profile

Here is an easy way to get the EAP configuration from your desktop using the rasphone tool that is shipped in the box.

1. Run rasphone.exe.

   

2. If you don't currently have any VPN connections and you see the following message, click OK.

   

3. Select Workplace network in the wizard.

   

4. Enter any dummy information for the internet address and connection name. These can be fake since it does not impact the authentication parameters.

   

5. Create a fake VPN connection. In the UI shown below, click Properties.

   

6. In the Test Properties dialog, click the Security tab.

   

7. In the Security tab, select Use Extensible Authentication Protocol (EAP) radio button.

   

8. From the drop down menu, select the EAP method that you want to configure. Then click Properties to configure as needed.

   

9. Switch over to PowerShell and use the following cmdlets to retrieve the EAP configuration XML.

   Get-VpnConnection -Name Test
   

   Here is an example output.

   Name                  : Test
   ServerAddress         : 1.1.1.1
   AllUserConnection     : False
   Guid                  : {EC87F6C9-8823-416C-B92B-517D592E250F}
   TunnelType            : Automatic
   AuthenticationMethod  : {Eap}
   EncryptionLevel       : Optional
   L2tpIPsecAuth         : Certificate
   UseWinlogonCredential : False
   EapConfigXmlStream    : #document
   ConnectionStatus      : Disconnected
   RememberCredential    : True
   SplitTunneling        : False
   DnsSuffix             :
   IdleDisconnectSeconds : 0
   

   $a = Get-VpnConnection -Name Test
   

   $a.EapConfigXmlStream.InnerXml
   

   Here is an example output

   <EapHostConfig xmlns="http://www.microsoft.com/provisioning/EapHostConfig"><EapMethod><Type xmlns="http://www.microsoft.co
   m/provisioning/EapCommon">13</Type><VendorId xmlns="http://www.microsoft.com/provisioning/EapCommon">0</VendorId><VendorTy
   pe xmlns="http://www.microsoft.com/provisioning/EapCommon">0</VendorType><AuthorId xmlns="http://www.microsoft.com/provisi
   oning/EapCommon">0</AuthorId></EapMethod><Config xmlns="http://www.microsoft.com/provisioning/EapHostConfig"><Eap xmlns="h
   ttp://www.microsoft.com/provisioning/BaseEapConnectionPropertiesV1"><Type>13</Type><EapType xmlns="http://www.microsoft.co
   m/provisioning/EapTlsConnectionPropertiesV1"><CredentialsSource><CertificateStore><SimpleCertSelection>true</SimpleCertSel
   ection></CertificateStore></CredentialsSource><ServerValidation><DisableUserPromptForServerValidation>false</DisableUserPr
   omptForServerValidation><ServerNames></ServerNames></ServerValidation><DifferentUsername>false</DifferentUsername><Perform
   ServerValidation xmlns="http://www.microsoft.com/provisioning/EapTlsConnectionPropertiesV2">true</PerformServerValidation>
   <AcceptServerName xmlns="http://www.microsoft.com/provisioning/EapTlsConnectionPropertiesV2">true</AcceptServerName><TLSEx
   tensions xmlns="http://www.microsoft.com/provisioning/EapTlsConnectionPropertiesV2"><FilteringInfo xmlns="http://www.micro
   soft.com/provisioning/EapTlsConnectionPropertiesV3"><ClientAuthEKUList Enabled="true" /><AnyPurposeEKUList Enabled="true"
   /></FilteringInfo></TLSExtensions></EapType></Eap></Config></EapHostConfig>
   

   Note  You should check with MDM vendor if you need to pass this XML in escaped format. The XSDs for all EAP methods are shipped in the box and can be found at the following locations:

   • C:\Windows\schemas\EAPHost
   • C:\Windows\schemas\EAPMethods

    

EAP certificate filtering

In your deployment, if you have multiple certificates provisioned on the device and the Wi-Fi profile provisioned does not have a strict filtering criteria, you may see connection failures when connecting to Wi-Fi. The solution is to ensure that the Wi-Fi profile provisioned has strict filtering criteria such that it matches only one certificate.

Enterprises deploying certificate based EAP authentication for VPN/Wi-Fi can face a situation where there are multiple certificates that meet the default criteria for authentication. This can lead to issues such as:

• The user may be prompted to select the certificate.
• The wrong certificate may get auto selected and cause an authentication failure.

A production ready deployment must have the appropriate certificate details as part of the profile being deployed. The following information explains how to create or update an EAP Configuration XML such that the extraneous certificates are filtered out and the appropriate certificate can be used for the authentication.

EAP XML must be updated with relevant information for your environment This can be done either manually by editing the XML sample below, or by using the step by step UI guide. After the EAP XML is updated, refer to instructions from your MDM to deploy the updated configuration as follows:

• For Wi-Fi, look for the <EAPConfig> section of your current WLAN Profile XML (This is what you specify for the WLanXml node in the Wi-Fi CSP). Within these tags you will find the complete EAP configuration. Replace the section under <EAPConfig> with your updated XML and update your Wi-Fi profile. You might need to refer to your MDM’s guidance on how to deploy a new Wi-Fi profile.
• For VPN, EAP Configuration is a separate field in the MDM Configuration. Work with your MDM provider to identify and update the appropriate Field.

For information about EAP Settings, see https://technet.microsoft.com/library/hh945104.aspx#BKMK_Cfg_cert_Selct

For information about generating an EAP XML, see EAP configuration

For more information about extended key usage, see http://tools.ietf.org/html/rfc5280#section-4.2.1.12

For information about adding extended key usage (EKU) to a certificate, see https://technet.microsoft.com/library/cc731792.aspx

The following list describes the prerequisites for a certificate to be used with EAP:

• The certificate must have at least one of the following EKU (Extended Key Usage) properties:

  • Client Authentication
    • As defined by RFC 5280, this is a well-defined OID with Value 1.3.6.1.5.5.7.3.2
  • Any Purpose
    • An EKU Defined and published by Microsoft, is a well-defined OID with value 1.3.6.1.4.1.311.10.12.1. The inclusion of this OID implies that the certificate can be used for any purpose. The advantage of this EKU over the All Purpose EKU is that additional non-critical or custom EKUs can still be added to the certificate for effective filtering.
  • All Purpose
    • As defined by RFC 5280, If a CA includes extended key usages to satisfy some application needs, but does not want to restrict usage of the key, the CA can add an Extended Key Usage Value of 0. A certificate with such an EKU can be used for all purposes.

• The user or the computer certificate on the client chains to a trusted root CA

• The user or the computer certificate does not fail any one of the checks that are performed by the CryptoAPI certificate store, and the certificate passes requirements in the remote access policy.

• The user or the computer certificate does not fail any one of the certificate object identifier checks that are specified in the Internet Authentication Service (IAS)/Radius Server.

• The Subject Alternative Name (SubjectAltName) extension in the certificate contains the user principal name (UPN) of the user.

The following XML sample explains the properties for the EAP TLS XML including certificate filtering.

Note

  For PEAP or TTLS Profiles the EAP TLS XML is embedded within some PEAP or TTLS specific elements.

 

<EapHostConfig xmlns="http://www.microsoft.com/provisioning/EapHostConfig">
 <EapMethod>
  <Type xmlns="http://www.microsoft.com/provisioning/EapCommon">13</Type>
  <!--The above property defines the Method type for EAP, 13 means EAP TLS -->

  <VendorId xmlns="http://www.microsoft.com/provisioning/EapCommon">0</VendorId>
  <VendorType xmlns="http://www.microsoft.com/provisioning/EapCommon">0</VendorType>
  <AuthorId xmlns="http://www.microsoft.com/provisioning/EapCommon">0</AuthorId>
  <!--The 3 properties above define the method publishers, this is seen primarily in 3rd party Vendor methods.-->
  <!-- For Microsoft EAP TLS the value of the above fields will always be 0 --> 
 </EapMethod>
 <!-- Now that the EAP Method is Defined we will go into the Configuration --> 
 <Config xmlns="http://www.microsoft.com/provisioning/EapHostConfig">
  <Eap xmlns="http://www.microsoft.com/provisioning/BaseEapConnectionPropertiesV1">
   <Type>13</Type>
   <EapType xmlns="http://www.microsoft.com/provisioning/EapTlsConnectionPropertiesV1">
    <CredentialsSource>
     <!-- Credential Source can be either CertificateStore or SmartCard --> 
     <CertificateStore>
      <SimpleCertSelection>true</SimpleCertSelection>
      <!--SimpleCertSelection automatically selects a cert if there are mutiple identical (Same UPN, Issuer, etc.) certs.-->
      <!--It uses a combination of rules to select the right cert-->
     </CertificateStore>
    </CredentialsSource>
    <ServerValidation>
     <!-- ServerValidation fields allow for checks on whether the server being connected to and the server cert being used are trusted -->
     <DisableUserPromptForServerValidation>false</DisableUserPromptForServerValidation>
     <ServerNames/>
    </ServerValidation>
    <DifferentUsername>false</DifferentUsername>
    <PerformServerValidation xmlns="http://www.microsoft.com/provisioning/EapTlsConnectionPropertiesV2">false</PerformServerValidation>
    <AcceptServerName xmlns="http://www.microsoft.com/provisioning/EapTlsConnectionPropertiesV2">false</AcceptServerName>
    <TLSExtensions xmlns="http://www.microsoft.com/provisioning/EapTlsConnectionPropertiesV2">
     <!-- For filtering the relevant information is below -->
     <FilteringInfo xmlns="http://www.microsoft.com/provisioning/EapTlsConnectionPropertiesV3">
      <CAHashList Enabled="true">
       <!-- The above implies that you want to filter by Issuer Hash -->
       <IssuerHash>ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
        <!-- Issuing certs thumbprint goes here-->
       </IssuerHash>
       <!-- You can add multiple entries and it will find the list of certs that have at least one of these certs in its chain--> 
      </CAHashList>
      <EKUMapping>
       <!-- This section defines Custom EKUs that you may be adding-->
       <!-- You do not need this section if you do not have custom EKUs -->
       <!-- You can have multiple EKUs defined here and then referenced below as shown -->
       <EKUMap>
        <EKUName>
         <!--Add a friendly Name for an EKU here for example -->ContostoITEKU</EKUName> 
        <EKUOID>
         <!--Add the OID Value your CA adds to the certificate here, for example -->1.3.6.1.4.1.311.42.1.15</EKUOID> 
       </EKUMap>
        <!-- All the EKU Names referenced in the example below must first be defined here
       <EKUMap>
        <EKUName>Example1</EKUName>
        <EKUOID>2.23.133.8.3</EKUOID>
      
       </EKUMap>
       <EKUMap>
        <EKUName>Example2</EKUName>
        <EKUOID>1.3.6.1.4.1.311.20.2.1</EKUOID>
       </EKUMap>
       -->
      </EKUMapping>
      <ClientAuthEKUList Enabled="true">
       <!-- The above implies that you want certs with Client Authentication EKU to be used for authentication -->
       <EKUMapInList>
        <!-- This section implies that the certificate should have the following custom EKUs in addition to the Client Authentication EKU -->
        <EKUName>
         <!--Use the name from the EKUMap Field above-->ContostoITEKU</EKUName> 
       </EKUMapInList>
       <!-- You can have multiple Custom EKUs mapped here, Each additional EKU will be processed with an AND operand -->
       <!-- For example, Client Auth EKU AND ContosoITEKU AND Example1 etc. -->
       <EKUMapInList>
        <EKUName>Example1</EKUName>
       </EKUMapInList>
      </ClientAuthEKUList>
      <AllPurposeEnabled>true</AllPurposeEnabled>
      <!-- Implies that a certificate with the EKU field = 0 will be selected --> 
      <AnyPurposeEKUList Enabled="true"/>
      <!-- Implies that a certificate with the EKU oid Value of 1.3.6.1.4.1.311.10.12.1 will be selected --> 
      <!-- Like for Client Auth you can also add Custom EKU properties with AnyPurposeEKUList (but not with AllPurposeEnabled) -->
      <!-- So here is what the above policy implies. 
      The certificate selected will have
      Issuer Thumbprint = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
      AND
      ((Client Authentication EKU AND ContosoITEKU) OR (AnyPurposeEKU) OR AllPurpose Certificate)
      
      Any certificate(s) that match these criteria will be utilised for authentication
      -->
     </FilteringInfo>
    </TLSExtensions>
   </EapType>
  </Eap>
 </Config>
</EapHostConfig>

Note

  The EAP TLS XSD is located at %systemdrive%\Windows\schemas\EAPMethods\eaptlsconnectionpropertiesv3.xsd

 

Alternately you can use the following procedure to create an EAP Configuration XML.

1. Follow steps 1 through 7 in the EAP configuration topic.

2. In the Microsoft VPN SelfHost Properties dialog box, select Microsoft : Smart Card or other Certificate from the drop down (this selects EAP TLS.)

   

   Note  For PEAP or TTLS, select the appropriate method and continue following this procedure.

    

3. Click the Properties button underneath the drop down menu.

4. In the Smart Card or other Certificate Properties menu, select the Advanced button.

   

5. In the Configure Certificate Selection menu, adjust the filters as needed.

   

6. Click OK to close the windows to get back to the main rasphone.exe dialog box.

7. Close the rasphone dialog box.

8. Continue following the procedure in the EAP configuration topic from Step 9 to get an EAP TLS profile with appropriate filtering.

Note

  You can also set all the other applicable EAP Properties through this UI as well. A guide for what these properties mean can be found in the Extensible Authentication Protocol (EAP) Settings for Network Access topic.