Securing Active Directory in 2026

In a modern threat landscape, Active Directory is the primary target for ransomware and lateral movement. Hardening AD is no longer a “one-time” task; it is a continuous posture of reducing the attack surface and enforcing **Least Privilege**.

Critical Hardening Pillars

IDENTITY PROTECTION

1. Implement Tiered Administration

Protect your Domain Admins by enforcing the Enterprise Access Model. High-privilege accounts must only log in to high-privilege systems (Tier 0). Never allow a Domain Admin to log into a workstation where a credential harvester might be waiting.

GPO SECURITY

2. Disable Print Spooler on Domain Controllers

The Print Spooler service remains one of the most exploited vulnerabilities (PrintNightmare). Unless your DC is literally printing paper, disable it immediately.

# PowerShell to disable Spooler on DCs
Stop-Service -Name Spooler -Force
Set-Service -Name Spooler -StartupType Disabled

NETWORK HYGIENE

3. Restrict SMB and NTLM Traffic

Legacy protocols are a goldmine for attackers. Transition toward SMB Signing and Encryption, and audit NTLM usage with the goal of moving strictly to Kerberos armoring.

MONITORING

4. Honeytoken & Bait Accounts

Deploy “Honeytoken” accounts with highly attractive names (e.g., Admin_Backup_Service). These accounts should have no real permissions; any login attempt should trigger a SEV-1 alert in your SIEM.

Recommended Toolkit

• PingCastle: For rapid AD security auditing.
• Purple Knight: For identifying indicators of exposure.
• Microsoft Defender for Identity: To monitor on-prem signals in the cloud.