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



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This series is comprised of different parts, listed below.

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.

    join domain.png

    In the System Properties screen, click on Change.

    system properties.png

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

    member of domain.png

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

    windows noob credentials.png

    click OK and click OK again when prompted with the welcome

    welcome to the.png

    click OK

    restart now.png

    Click OK, click Close then click Restart Now.

    restart computer now.png

    After the reboot login to the domain as windowsnoob\administrator

    login as administrator.png

    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.

    add server roles.png

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

    role based or feature based.png

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

    select a server from the pool.png

    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.

    add features for iis.png

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

    web server iis selected.png

    On Select features click Next.

    select features.png

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

    intro to IIS.png

    Accept the defaults and click Next.

    iis defaults.png

    on the Confirm Installation Selections screen click Install.

    confirm installation selections.png

    Click Close when the installation succeeds.

    iis installed.png

    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.

    CertEnroll folder.png

    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.

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

    share this folder.png

    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.

    cert publishers.png

    imageproxy.php?img=&key=588032a05702b0f0On Permissions for CertEnroll dialog box, select the Cert Publishers group and then in the Allow column select Change permission.

    change.png

    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.

    cert publishers ntfs permissions.png

    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.

    modify added.png

    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

    imageproxy.php?img=&key=588032a05702b0f0 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.

    add virtual directory.png

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

    adding virtual directory.png

    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.

    Enable directory browsing.png

    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.

    enable double escaping.png

    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

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

    add DNS record.png

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

    ping URL.png

    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.

    port forward configured.png

    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

    public url.png

    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

     

     

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