**One Breach at Tier 0 Could Mean Total Network Compromise**

Active Directory (AD) is the backbone of identity management in 90% of Fortune 1000 companies—and that makes it a prime target. Cyber attackers know that if they can breach Tier 0, the highest privilege level in an organization’s IT environment, they can take control of the entire network.

**Tier 0 includes:**

* Active Directory itself

* Domain Controllers

* Identity tools like ADFS, Azure AD Connect, and more

To address this risk, Microsoft recommends a hardened security approach:

* **Just-in-Time (JIT) access** to reduce the window of opportunity for attackers

* **No standing admin privileges** to eliminate persistent high-level access

* **Isolate Tier 0 systems** from lower-tier networks and systems to limit lateral movement

Without these protections, a single compromise at Tier 0 can result in a catastrophic breach, granting attackers unfettered access to all systems and data. Securing this tier isn’t optional—it’s critical.