Hidden Admins: How Non-Standard Primary Group IDs Expose Active Directory to Risk

Welcome to Guardians of the Directory, the podcast where we break down real-world threats, best practices, and insights in Active Directory, Entra ID, and Microsoft identity security.

In today’s episode, Craig Birch dives into one of Active Directory’s oldest — and most quietly dangerous — features: the primaryGroupID. While originally designed for POSIX compatibility and legacy systems, this attribute can now be misused to grant hidden privileges, bypass group auditing, and create stealth admin access.

🔍 In this episode, you'll learn:

• What the primaryGroupID attribute is and why it still exists

• Why anything other than 513 (Domain Users) should raise red flags

• How attackers can leverage this setting to hide elevated privileges

• How to detect non-standard values using PowerShell

• How to safely remediate misconfigured accounts

• Why real-time detection with Cayosoft Guardians is a smarter defense

Craig walks you through not just how to fix the problem — but how to prevent it entirely with intelligent alerting, automation, and policy enforcement.