Happy birthday, Active Directory!

25 years ago Microsoft officially launched Active Directory (AD) as a core feature of Windows 2000 Server, marking a transformative shift in enterprise identity management. Fast forward a quarter of a century, and while Windows 2000 Server has long vanished from data centres worldwide, Active Directory remains as relevant as ever.

Such longevity is virtually unheard of in the technology world. Most enterprise solutions are rewritten, rebranded or replaced within a decade — but not AD. Far from being a relic of the past, it continues to be deeply embedded in modern IT infrastructure, serving as the backbone of identity and access management for countless organisations.

The continued relevance of Active Directory

Active Directory is still a foundational component for most medium-to-large enterprises, ensuring that hundreds of millions of users worldwide can seamlessly access corporate resources. Being ‘AD integrated’ (which also means ‘AD dependent’) has been a requirement for most on-premises software for many years.

Interestingly, AD is arguably more important today than it was 10 years ago. Why? Because as organisations increasingly shift to the cloud, hybrid identity architectures have evolved to extend AD identities into cloud service providers like Microsoft Entra ID (formerly Azure AD). This hybrid approach allows enterprises to maintain their existing AD-based authentication while enabling cloud adoption, providing a bridge between on-prem infrastructure and modern SaaS applications.

Despite newer cloud-based identity solutions, many businesses are still tied to AD, simply because of the enormous investment in AD-integrated applications, policies and workflows that have been built up over two decades. In some cases, replacing AD isn’t just a technical challenge — it’s a business risk.

Is Active Directory dead?

I get asked this all the time. My answer? Absolutely not.

Yes, Active Directory is mature. And while Microsoft has largely shifted focus to cloud-based identity solutions, the reality is that most IT environments are still deeply dependent on AD. When I conduct polls in my webinars, I typically ask attendees when they plan to shut down AD. Almost three-quarters say “never”.

To be fair, many of these respondents would like to move away from AD for one overwhelming reason: security. Organisations know that modernising identity security is critical. AD has long been a target for cyber attacks, with credential theft, Kerberoasting and NTLM relay attacks being among the many serious risks associated with this directory service. However, replacing AD entirely isn’t a simple flick of the switch — you must first replace or shut down the applications that depend on it. This requires complete refactoring of applications, policies and access controls, which can be both expensive and risky.

Today, AD and Entra ID identity systems are used in over 90% of networks globally. As the default identity system, AD becomes the primary target for attackers. AD is deeply integrated into most organisations and is crucial to IT operations, effectively holding the ‘keys to the kingdom’. If attackers gain privileged access to AD, they can control any resources within the organisation that relies on AD — which is most of them.

AD is therefore a significant target for threat actors aiming to conduct reconnaissance and elevate privileges within a compromised network.

At the same time, cloud identity solutions — while providing advantages in scalability and security — are proving increasingly susceptible to cyber attacks themselves. Just look at the recent high-profile breaches affecting cloud identity providers. No system is invulnerable, which is why many enterprises are choosing a hybrid approach, retaining AD while implementing Zero Trust principles and modern authentication methods like passwordless logins and conditional access policies.

The future of Active Directory

So, where does AD go from here? While pure on-premises AD deployments may eventually decline, hybrid models will continue to thrive. Organisations will keep leveraging AD for legacy applications while shifting new workloads to cloud-based authentication.

Will we be celebrating AD’s 30th birthday, or 40th? I wouldn’t bet against it. It may not be flashy, but Active Directory has quietly outlasted countless other technologies, proving itself as one of the most resilient enterprise IT tools ever created. So, here’s to 25 years of Active Directory — a technology that has proved its staying power, shaped enterprise IT as we know it, and continues to power the digital workforce every single day. *Sean Deuby is Principal Technologist at Semperis.

Top image credit: iStock.com/Nutthaseth Vanchaichana