Tag: How-to (Page 1 of 3)

Part 4: Using Certificate Enrollment Services in Practice

August 8, 2026 / Michael Waterman / 0 Comments

In the previous parts of this series, I’ve looked at the architecture behind Microsoft Certificate Enrollment Services and built both the Certificate Enrollment Policy Web Service (CEP) and Certificate Enrollment Web Service (CES). At this point, all the server-side components are in place. But having a working CEP and CES infrastructure is only half the story. Ultimately, a client needs to know where to retrieve certificate enrollment policy, determine which certificate templates it is allowed to use, discover the appropriate enrollment service, and finally submit a certificate request. That’s what I will show you in this part.

I will configure Windows clients to use our CEP service in two different ways. First, I will use Group Policy, which is the obvious choice for centrally managed domain-joined systems. After that, I will configure the enrollment policy locally, which is useful for individual systems and becomes particularly interesting when working with devices that cannot rely on Active Directory Group Policy. I will then follow the complete process from policy discovery to certificate enrollment and look at what Windows is actually doing behind the scenes.

Part 3: Installing the Certificate Enrollment Web Service (CES)

August 3, 2026 / Michael Waterman / 0 Comments

In the previous article, we deployed the Certificate Enrollment Policy Web Service (CEP) and configured support for Kerberos, Username/Password, and Client Certificate authentication. Clients can now successfully retrieve certificate enrollment policies over HTTPS using the XCEP protocol. However, while the policy infrastructure is now in place, clients still have no way to request certificates.

In this article, I’ll complete the Microsoft Certificate Enrollment Services architecture by deploying the Certificate Enrollment Web Service (CES). I’ll prepare Active Directory, configure a dedicated Group Managed Service Account (gMSA), install IIS, deploy the CES role, configure the supported authentication methods, and validate the deployment using PowerShell. By the end of this article, you’ll have a fully operational Certificate Enrollment Web Service capable of securely processing certificate requests over HTTPS using the WSTEP protocol.

Part 2: Installing the Certificate Enrollment Policy Web Service (CEP)

August 3, 2026 / Michael Waterman / 0 Comments

In the first article of this series, I explored the architecture behind Microsoft Certificate Enrollment Services (CEP & CES) and discussed why Microsoft introduced these web services.I looked at the differences between traditional Active Directory Certificate Services enrollment and the HTTPS-based enrollment model, explained the XCEP and WSTEP protocols, and followed the complete certificate enrollment process from start to finish. Now it’s time to move from theory to implementation.

In this article, I’ll build a complete Certificate Enrollment Policy Web Service (CEP) from scratch using PowerShell. Rather than simply installing the Windows role, I’ll also prepare Active Directory, create the required security groups, configure a Group Managed Service Account (gMSA), install IIS, configure the supported authentication methods, and validate that the deployment is functioning correctly. By the end of this article, you’ll have a fully operational Certificate Enrollment Policy Web Service capable of serving enrollment policies over HTTPS using Kerberos, Username/Password, or Client Certificate authentication.

What’s a Certificate Anyway

July 16, 2026 / Michael Waterman / 0 Comments

One of the questions I get asked most often during assignments or workshops isn’t really about Certificate Revocation Lists (CRLs), OCSP, certificate templates or PKI in general. It’s much simpler than that.

“What’s a certificate anyway?”

Well actually, I sometimes start with the question, “So, can anyone explain to me what a certificate is or what it represents?”. You would think, it seems like an easy question to answer. Some people will tell you it’s your public key. Others will say it’s your digital identity. While both answers contain some truth, rarely the complete story is told. A digital certificate is much more than a single piece of information. It contains an identity, a public key, validity information, a collection of extensions, and much more. More importantly, all of that information is cryptographically protected by a trusted Certificate Authority (CA).

In other words, a certificate is a digitally signed document that binds an identity to a public key, with a couple of extensions. That digital signature allows anyone who trusts the issuing CA to verify that the certificate has not been modified and that the binding between the identity and the public key is authentic. But what exactly is inside a certificate? What does a Certificate Authority actually sign? And why does changing just a single character invalidate the entire certificate?

Let’s take a look under the hood of an X.509 certificate.

How Merkle Tree Certificates Work

June 27, 2026 / Michael Waterman / 0 Comments

For more than 35 years, X.509 certificates have formed the foundation of digital trust on the Internet and in many organizations alike. From HTTPS and VPNs to enterprise authentication and code signing, the basic architecture has remained unchanged. As we enter the post-quantum era, however, it may not be the cryptographic algorithms that need the biggest overhaul, but the certificate model itself.

Imagine a Certificate Authority such as Let’s Encrypt issuing hundreds of millions of post-quantum certificates. Every one of those certificates now carries a digital signature that is significantly larger than today’s RSA or ECC signatures. Suddenly, TLS handshakes become larger, certificate chains consume more bandwidth, Certificate Transparency logs grow faster, and browsers have considerably more data to process. Everything just slows down.

The challenge is no longer whether post-quantum cryptography works. The challenge is whether the X.509 certificate architecture can continue to scale in a post-quantum world. This is exactly the problem that Merkle Tree Certificates (MTC) are designed to solve.

Building a Highly Available CRL and AIA Distribution Platform for AD CS

June 4, 2026 / Michael Waterman / 0 Comments

Last time I wrote about the why a Certificate Revocation List (CRL) should be available for the majority of services that make use of certificates. One of those prime examples is the use of smartcards. When revocation can’t be checked, you simply can not logon. Most Microsoft PKI deployments start with a single web server hosting the CRL Distribution Point (CDP) and Authority Information Access (AIA) locations. While this works well for smaller environments or labs, it introduces a single point of failure. If the web server becomes unavailable, certificate revocation checking may fail and certificate validation can be disrupted across the environment.

Building Windows images with Packer on Hyper-V

April 29, 2026 / Michael Waterman / 0 Comments

Back in December, I published a blog on building Windows images using Packer on Proxmox. That setup worked well, but like most things in infrastructure, you start tweaking, refining, and eventually rethinking parts of it. if you’re anything like me, this needs to work perfectly…. and that takes a lot of time. Over the past months, I’ve streamlined the entire workflow. Less friction, more consistency, and most importantly, something I can reuse across different Windows versions without thinking twice. And best of all, it’s now fully functional on Microsoft Hyper-V!

In this post, I’ll walk you through my current setup for building Windows Server images on Hyper-V using Packer. This is the version I actually use today as I moved back to Windows Hyper-V for my lab setup, not just something that works, but something that’s predictable and maintainable and was really fun to make.

Monitoring Windows Firewall logs with Azure Monitor

April 21, 2026 / Michael Waterman / 2 Comments

In a previous blog, “On-prem Conditional Access You Never Knew You Had” I explored how the built-in Windows Firewall can be used as a powerful control mechanism to restrict access to systems, effectively bringing conditional access concepts to on-premises environments. The response to that post was overwhelming, with over 23,000 views on Reddit alone. Clearly, many organizations are interested in rethinking how they use the Windows Firewall beyond its default, often permissive configuration, and so should you/ But before you can confidently start restricting access, there is a fundamental question you need to answer:

What is actually being used in your environment?

In many cases, firewall rules have grown organically over time. Ports are opened “temporarily,” (read: we forget, so they will be open forever) exceptions are made for specific systems, and over the years, the rule set becomes difficult to understand, let alone control or optimize. Tightening those rules without proper insight is risky and can easily break critical services.

On-prem conditional access you never knew you had

April 17, 2026 / Michael Waterman / 5 Comments

We often associate Conditional Access with Entra ID, Cloud apps, and Zero Trust.
But long before cloud-native policy engines existed, Windows already had a way to enforce identity-based access between endpoints, and I mean really long ago. I would make the claim that we could go back to February of the year 2000, when Windows 2000 saw the light of day. Years later in the era of Windows Vista and Windows 7, we got the Windows Advanced Firewall and that can do so much more than just block or allow a port, I think it’s a really cool piece of software. The combination of Windows Firewall, Kerberos and IPsec effectively gives you on-prem Conditional Access for east-west traffic. In this post I’ll tell you a bit of history, which problems my blog solves and why you want to start using it. And for the folks that see the word “IPsec”, trust me, I’ll make it easy to use, promise!

Let’s dive in!

Gone in a cipher, wiping deleted data the native windows way

April 5, 2026 / Michael Waterman / 1 Comment

Deleting a file in Windows rarely means the data is actually gone. In most cases, the file system simply removes the reference to the file while the underlying data remains untouched in unallocated space until it is overwritten. That is exactly why forensic tools can often recover deleted photos, documents, and other files long after a user believes they are gone.

When organizations need to prepare systems for redeployment, decommissioning, or internal reuse, many immediately look at commercial wiping solutions. What is often overlooked is that Windows already includes a native tool capable of securely overwriting deleted data: cipher.

And yes, it’s been there for a really long time.