How can I configure PKI in a lab on Windows Server 2016 - Part 3

[anyweb]

This series is comprised of different parts, listed below.

• Part 1 - Introduction and server setup
• Part 2 - Install and do initial configuration on the Standalone Offline Root CA
• Part 3 - Prepare the HTTP Web server for CDP and AIA Publication (this part)
• Part 4 - Post configuration on the Standalone Offline Root CA
• Part 5 - Installing the Enterprise Issuing CA
• Part 6 - Perform post installation tasks on the Issuing CA
• Part 7 - Install and configure the OCSP Responder role service
• Part 8 - Configure AutoEnroll and Verify PKI health

In part 1 of this series, you configured your LAB for a 2 tier PKI hierarchy running on Windows Server 2016. You used PowerShell to create some virtual machines, and then installed Windows Server 2016,  Windows 10 Enterprise version 1803 and optionally Smoothwall 3.1 before configuring the IP address scheme and Computer Names on the virtual machines. Finally you configured ADDS on DC01 so that you have a working Domain Controller for the rest of this LAB. In part 2 you installed and did the initial configuration on the Standalone Offline Root CA. In this part you will prepare the HTTP Web Server for CDP and AIA Publication. But before you get started with that, please have a read below of what a CDP and AIA actually are.

What is a CDP ?

A CDP (CRL Distribution Point) is an extension that contains links to the CRL of the issuer of the certificate which is being verified (1).

Quote

The certificate revocation list distribution point (CDP) is a path represented as one or more attributes on every certificate issued by a PKI. This path, literal, share, lightweight directory access protocol (LDAP), and HTTP is clearly defined and uses variables to simplify the configuration. After definition, the PKI publishes CRLs and delta CRLs (if you choose to publish delta CRLs) for the computers that hold certificates that it has issued (2).

What is an AIA ?

An AIA (Authority Information Access) is an extension that contains links to the certificate of the issuer of the certificate which is being verified.

Step 1. Join the web server computer to the domain

When you installed the web server virtual machine (#11_Webserver) in part 1, it was workgroup joined. To join the domain do as follows. Logon to the web server virtual machine as Administrator. In Windows File Explorer, right click on This PC and choose Properties. Click on Change Settings beside Computer name, domain and workgroup settings.

In the System Properties screen, click on Change.

In the Member of field select Domain and enter the domain name you configured in part 1.

enter credentials required for Domain join membership (eg: windowsnoob\administrator)

click OK and click OK again when prompted with the welcome

click OK

Click OK, click Close then click Restart Now.

After the reboot login to the domain as windowsnoob\administrator

Alternatively, to join the domain automatically, use the joindomain.ps1 PowerShell script which you can download from here.

JoinDomain.ps1

1. Copy the script to C:\Scripts on the webserver.

2. Edit the variables (lines 16-18) as desired before running.

3. Start Windows PowerShell ISE as Administrator and run the script by clicking on the green triangle.

Step 2. Install the Web Server (IIS) Role

Logon to the web server as windowsnoob\administrator and open Server Manager, select Add Roles and Features. In the wizard that appears click Next.

Click Next and select Role-based or feature-based installation.

Click Next and Select Select a server from the server pool, ensure that webserver.windowsnoob.lab.local is selected.

Click Next and select Web Server(IIS) from the choices available on the Select server roles page, if prompted to Add features that are required for Active Directory Certificate Services, click Add features.

Here you can see the Web Server (IIS) role selected.

On Select features click Next.

In the introduction to Web Server (IIS) screen, select Next.

Accept the defaults and click Next.

on the Confirm Installation Selections screen click Install.

Click Close when the installation succeeds.

Step 3. Create a CertEnroll Folder and grant Share & NTFS Permissions to the Cert Publishers group

Create the CertEnroll Folder

Now you need to create a shared folder where certificates and delta certificates can be stored from the PKI infrastructure. Open Windows File Explorer and then browse to the C:\ drive, Create a folder called CertEnroll at the root of the drive.

Share the CertEnroll folder

Right-click on the CertEnroll folder and select Properties. On the CertEnroll Properties page select the Sharing tab to configure share permissions.

Click on the Advanced Sharing option and then select Share this folder.

Click on Permissions and then click Add, on the Select Users or Groups page, in the Enter the object names to select, type windowsnoob\Cert Publishers and then click OK.

 

On Permissions for CertEnroll dialog box, select the Cert Publishers group and then in the Allow column select Change permission.

Click OK twice to go back to the CertEnroll Properties page.    

Edit NTFS permissions on the CertEnroll folder

Select the Security tab and click Edit to configure NTFS permissions. On Permissions for CertEnroll page click Add. On the Select Users or Groups page, under the Enter the object names to select, enter windowsnoob\Cert Publishers and then click OK.

On the Permissions for CertEnroll page highlight the Cert Publishers group and then under the Allow column select the Modify permission and then click OK.

On the Permissions for CertEnroll page, click OK to close the window and click OK again to close CertEnrolls properties page.

Step 4. Create a Virtual Directory in IIS

Ensure you are logged on to webserver as windowsnoob\Administrator. Click Start, select Administrative Tools and then select Internet Information Services (IIS) Manager. In the Connections pane, expand WEBSERVER and then expand Sites. Right-click on Default Web Site and select Add Virtual Directory.

On the Add Virtual Directory page, in Alias, type CertEnroll and for Physical path, type C:\Certenroll, and then click OK.

In the Connections pane, under the Default Web Site, ensure the CertEnroll virtual directory is selected then in the CertEnroll Home pane, double-click on Directory Browsing.
In the Actions pane click Enable.

Step 4. Enable Double Escaping on the IIS Server

Allowing double escaping makes it possible for the web server to host Delta CRLs. For more information about this see KB Article 942076 (3).

Ensure you are logged on to the webserver as windowsnoob\Administrator. Open an Administrative Command Prompt. Then enter the following

cd %windir%\system32\inetsrv\ 

and press ENTER. Type following command and press Enter.

Appcmd set config "Default Web Site" /section:system.webServer/Security/requestFiltering -allowDoubleEscaping:True

 Type the following to restart IIS.

iisreset

and press ENTER.

Step 5. Create a DNS record for externally accessible website address

To answer requests for OCSP and CRL, AIA via a publicly available URL, login to your DNS provider and create a new DNS record for your chosen public URL, eg: http://pki.windows-noob.com

Note: http://pki.windows-noob.com is a website address that I own and use, and I'm using it in this guide to show you what you need to do, obviously you need to use your own website address, for example http://pki.yourdomain.com.

This should point to the IP address of your internet connection that is being shared via the smoothwall.

Once it's setup, you can verify pinging the URL

Lastly, you need to configure your Smoothwall (or use another method) to port forward port 80 (http) internet requests to the webserver. To do that, login to https://192.168.11.199:441 (the Smoothwall IP address) via the Internet Explorer Web browser on the WebServer. Note that you may have to disable IE enhanced security information temporarily to allow access. Once connected, login as Admin/password, which you defined when you installed the Smoothwall. Below you can see the Port Forward I've configured for port 80 requests.

After doing so, anyone can browse to http://pki.windows-noob.com using a web browser which means they'll be able to retrieve CRL's when they are published to http://pki.windows-noob.com/certenroll

Join me in part 4 to further configure the Standalone Offline Root CA.

Recommended reading

(1) - https://www.sysadmins.lv/blog-en/root-certification-authority-ca-cdp-and-aia-extension-question.aspx

(2) - https://blogs.technet.microsoft.com/nexthop/2012/12/17/updated-creating-a-certificate-revocation-list-distribution-point-for-your-internal-certification-authority/

(3) - http://support.microsoft.com/kb/942076

 

 

[Mayur]

Hello Naill, Hope you are doing good. I have added the DNS entry but i am not able to browse it. i am getting the error

[anyweb]

Hi Muyar,

thanks,

so you configured the DNS cname in your DNS provider but it's not redirecting to your webserver, is that correct ? did you also configure smoothwall ?

[Mayur]

Hello Naill,

I am using Vyos as a virtual appliance for connecting my SCCM servers to internet.

Vyos has internal DHCP as 192.168.3.X and External IP is 192.168.1.X

I have assigned pki.mydomain.xxx IP as 192.168.1.XXX at Godaddy.com

i can ping  pki.mydomain.xxx and getting the IP address 192.168.1.XXX as configured in GoDaddy.com

Kindly can you help me what exact i am missing or need to change?

 

For Refrence,

I have configured Vyos as :

 

set nat destination rule 10 description 'Port Forward: HTTP to 192.168.1.XXX'
set nat destination rule 10 destination port '80'
set nat destination rule 10 inbound-interface 'eth0'
set nat destination rule 10 protocol 'tcp'
set nat destination rule 10 translation address '192.168.1.XXX'

 

Thanks

Edited August 7, 2020 by Mayur

[anyweb]

hi Muyar,

the 192.168.x.x address at godaddy will never work, as that's a local lab ip range, it must instead point to the actual internet ip address you have in your lab (use www.whatismyipaddress.com to find out)

[Mayur]

Hello Naill, Thanks for the fast response.

I have changed the IP as per your suggestion. kindly can you verify in the enclosed screenshot if this is right ?

[anyweb]

hi Muray,

this does not look like my setup, but then again DNS providers have different views of the same thing, obviously you need to use your own domain name (eg: pki.mydomain.com) and your own internet ip address

 

once you've made the change in your DNS provider, you can test if it works by pinging the url and see what ip address it returns, or try and browse the url from your phone (external network)

 

for example you can ping or browse http://pki.windows-noob.com it should respond as the lab is online now.

[Mayur]

Hello Naill,

I have added the IP as you mentioned.

I am not able to ping nor browse from mobile/laptop/desktop.

 

Any help ?

[anyweb]

I am not able to ping nor browse from mobile/laptop/desktop. 

what do you mean you are not able to ping ? what ip address does it resolve to ?

[Mayur]

I am getting request timed out.

[anyweb]

well it could be your firewall solution that's blocking it, i don't know, I use smoothwall and it works just fine.

when you ping the url, it should return the correct ip address, does it ?