Strengthening NHI Security with Better Active Directory Hygiene

Read full article here: https://www.oasis.security/blog/why-should-active-directory-hygiene-be-part-of-your-nhi-security-program/?source=nhimg

Active Directory (AD) has been the backbone of enterprise identity for decades, designed around human users, passwords, and group structures. But in today’s hybrid and cloud-driven world, machines now outnumber humans by 20:1. Service accounts, APIs, bots, and workloads all rely on AD or sync into it, whether you realize it or not.

The problem? AD wasn’t designed with these non-human identities (NHIs) in mind. Old service accounts hang around, permissions pile up, and hidden dependencies sneak into critical systems. Without proper hygiene, AD becomes both a single point of failure and a goldmine for attackers.

Why Poor AD Hygiene Hurts NHI Security

• Stale Service Accounts → Orphaned accounts with standing privileges are often forgotten but remain exploitable.
• Over-Permissioned Identities → Nested groups and years of role sprawl make it impossible to know “who really has access.”
• Hidden Dependencies → “Retired” accounts might still be powering key apps, killing them can take production down.
• Audit & Compliance Headaches → Without clear ownership and lifecycle controls, AD quickly fails attestation tests.
• Hybrid Risks → When syncing AD with Entra or other cloud IdPs, dirty data in AD means dirty (and risky) data in the cloud.

What Strong AD Hygiene Looks Like in an NHI Program

Treat AD cleanup as an identity security foundation, not just a one-off IT project. A good hygiene program should include:

1. Continuous Discovery – Keep an always-up-to-date inventory of accounts (human + machine). Static spreadsheets and manual scripts don’t scale.
2. Usage & Dependency Mapping – Know which accounts are actually in use and what systems rely on them.
3. Entitlement Rationalization – Identify and fix over-privileged service accounts before attackers do.
4. Ownership & Attestation – Every account (especially NHIs) should have a named owner and renewal process.
5. Lifecycle Automation – Provision, rotate, and decommission machine accounts just like you would automate with CI/CD pipelines.
6. Continuous Monitoring – Watch for unusual patterns, such as service accounts suddenly accessing sensitive resources at odd hours.

The Bottom Line

Active Directory hygiene is no longer just about cleaning up messy user accounts. It’s about closing the gaps where NHIs hide, reducing your attack surface, and ensuring your hybrid environment stays resilient.

In a world where attackers target machine identities first, AD hygiene is NHI hygiene. Neglecting it risks not only compliance failures but also the keys to your most critical systems being left wide open.