Friday, August 25, 2017

Windows PE and Cisco ISE authentication 802.1x

Windows PE  and Cisco ISE authentication

This blog entry is intended to assist you when implementing a Cisco ISE next generation network across the organisation.  Without ISE profiles the SCCM Task Sequence will fail to connect to Distribution Points and the MDT database.  UNC paths are blocked and network access is restricted.
Cisco ISE by design will restrict network access to prevent unauthorized clients from simply plugging their equipment into the network and being routed like a authorised client.
Computer and User Authentication (explain in detailed section)
Cisco ISE profiles should be implemented in two ways; Cisco ISE profiles via Group Policy for domain joined systems, and to bake ISE profiles into the SCCM Boot Image.  The guide below will explain how to implement both configuration setups.

Tutorial - WinPE

Microsoft has detailed the two XML files required to achieve User Authentication when in WinPE here

Create an XML called "EthernetLANProfile.xml" containing the following. The Thumb Print detailed within <TrustedRootCA> should reflect a trusted Third Party Cert; This ISE certification should also be deployed to all Domain Joined systems for GPO ISE Profiles (see below Tutorial - OS)

<?xml version="1.0"?>
<!-- Sample LAN profile: EthernetLANProfile.xml" -->
<LANProfile xmlns="">
      <OneX xmlns="">
          <TrustedRootCA>1a 2b 3c 4d 56 78 90 aa bb cc dd ee ff 1a 2b 3c 4d 5e 6f</TrustedRootCA>

Create another XML file called "EAP_UserData.xml" containing the Service Account User Credentials.

<?xml version="1.0"?> <!-- Sample EAP user data: EAP_UserData.xml" --> <EapHostUserCredentials xmlns="" xmlns:eapCommon="" xmlns:baseEap=""> <EapMethod> <eapCommon:Type>25</eapCommon:Type> <eapCommon:AuthorId>0</eapCommon:AuthorId> </EapMethod> <Credentials xmlns:eapUser="" xmlns:xsi="" xmlns:baseEap="" xmlns:MsPeap="" xmlns:MsChapV2=""> <baseEap:Eap> <baseEap:Type>25</baseEap:Type> <MsPeap:EapType> <MsPeap:RoutingIdentity>onex\administrator</MsPeap:RoutingIdentity> <baseEap:Eap> <baseEap:Type>26</baseEap:Type> <MsChapV2:EapType> <MsChapV2:Username>SVC-Account-Name</MsChapV2:Username> <MsChapV2:Password>SVC-Account-password</MsChapV2:Password>
</MsChapV2:EapType> </baseEap:Eap> </MsPeap:EapType> </baseEap:Eap> </Credentials> </EapHostUserCredentials>

The SCCM Boot image will need to contain the WinPE-Dot3Svc Optional Component.  However, from my experience this component doesnt work in Windows 10 version 1607 or 1703.
The component wizard completes without errors however, the Dot3Svc cannot start in WinPE. Micrsoft have detailed the issue here

The component will need to be manually installed; download the KB4025632 MSU file from Windows Update Catalog- ##

The following two command will mount the Boot.wim Image and inject the Dot3Svc component.

Dism /Mount-Image /ImageFile:"C:\temp\WinPEx64\sources\boot.wim" /index:1 /MountDir:"C:\temp\WinPE_amd64-mount"

Dism /Add-Package /Image:"C:\temp\WinPE_amd64-mount" /PackagePath:"C:\temp\WinPEx64\windows10.0-kb4025632-x64_af86717e4eec306948b23cd1e82ff95640e51f5e.msu"

Before the Boot image is dismounted and copied to SCCM we also need to bake the ISE XML profiles into the Boot image.

Copy the EthernetLANProfile.xml & EAP_UserData.xml created earlier into the folder  "windows\system32"


Dism /Unmount-Image /MountDir:"C:\temp\WinPE_amd64-mount" /commit

After installing the component copy the wim to your Boot image source location.
Add a custom prestart command.  Open the Properties of the Boot image and go to the customization tab, enable the prestart command and type the following three commands (enable Dot3svc, import Ethernet Profile , import User Auth Profile"

cmd /c powershell -noninteractive -command net start dot3svc & cmd /c netsh lan add profile filename=%SYSTEMDRIVE%\windows\system32\EthernetLANProfile.xml interface=*  & cmd /c netsh lan set eapuserdata filename="%SYSTEMDRIVE%\windows\system32\EAP_UserData.xml" alluser=yes Interface=*

 Within the SCCM console update the distribution point to inject the SCCM binaries and distribute the WIM to your PXE enabled distribution Points.

Once the Boot image is loaded and you have typed your WinPE password (if present) the Prestart command will launch (Custom Hook).  WinPE will run the commands in the TSConfig.ini file located on the root of the X drive.

Before the list of Task Sequences (if available) are presented you will see a command window appear starting the dot3svc service and configure the User Authentication ISE profiles created earlier.

If you wanted to check that ISE is running before kicking off the Task Sequence then you can:-

Hit F8 for a command prompt (if enabled in the boot image)
 PowerShell -command Get-Service dot3svc 

You should see the service status as running

Running       dot3svc            Wired AutoConfig

No comments:

Post a Comment