Active Directory Security Fundamentals

Active Directory Security Fundamentals

Active Directory (AD) serves as the backbone of Windows enterprise security, providing centralized authentication and authorization services. Understanding AD security is crucial because compromising AD means compromising the entire Windows domain. Properly securing AD requires addressing multiple components, from domain controllers to group policies and trust relationships.

Domain Controllers require exceptional security attention as they store all domain credentials and enforce security policies. Implement dedicated Domain Controller security measures including physical security, network isolation, and restricted administrative access. Use Read-Only Domain Controllers (RODCs) in branch offices or less secure locations to limit credential exposure while maintaining authentication services.

Group Policy provides powerful security configuration capabilities across domain-joined systems. Security-focused GPOs can enforce password policies, implement software restrictions, configure Windows Firewall rules, and deploy security settings consistently. Properly structured OUs (Organizational Units) and well-designed GPOs ensure security settings apply appropriately without impacting system functionality.

Administrative tier separation represents a critical AD security concept. Implement separate administrative accounts for different privilege levels: Tier 0 for domain controllers and AD administration, Tier 1 for servers and applications, and Tier 2 for workstations. This separation prevents lateral movement from compromised lower-tier systems to critical infrastructure. Use Privileged Access Workstations (PAWs) for administrative tasks, ensuring administrative credentials never touch standard workstations.