Active Directory (AD) functions as the central control system of a Windows-based environment.

It determines:

• User identities and group membership
• Which workstations and servers are part of the environment
• How authentication and single sign-on work
• What actions users and systems are permitted to take through policies and permissions

When AD is compromised, the impact goes far beyond a single machine. In most cases, an attacker can:

• Change or reset credentials and create additional accounts
• Distribute harmful configurations or software using Group Policy
• Gain access to shared files, databases, email systems, VPNs, and internal applications

Control of AD effectively means control of the entire network.

That’s why, in internal security assessments, AD is the primary target:

• Establish initial access on a system joined to the domain
• Map out users, groups, computers, and applied policies
• Exploit weak configurations such as poorly secured service accounts, legacy protocols, or misconfigured group memberships to reach high-privilege or mission-critical systems

If an internal penetration test barely evaluates Active Directory, it doesn’t reflect the organization’s real risk—it only scratches the surface by testing a few isolated machines.