Active Directory Tiering & Least Privilege Implementation
Problem
A defence organisation was running a flat Active Directory structure with no administrative tiering. Domain Admins had the same credentials across workstations, servers, and domain controllers — a lateral movement risk that any competent attacker would exploit in minutes.
Approach
Designed and implemented a full NCSC-aligned AD tiering model. Tier 0, 1, and 2 separation with dedicated admin workstations, tiered service accounts, and granular Group Policy enforcement. Stripped back every privilege to the minimum required. Built the whole model around NCSC best practice for least privilege, with CIS benchmarks applied to every tier from day one.
Outcome
Complete privilege separation across all tiers. Lateral movement paths eliminated. Passed internal security review with zero findings — a first for the programme.