Welcome to the final installment of The Attacker’s Playbook. So far, we’ve covered exploiting the human element (Part 1), finding unlocked doors (Part 2), and using forgotten keys to the kingdom (Part 3) to get inside a network.
But initial access is just the beginning. The real damage is done when we move through the internal network, abusing trust and misconfigurations to turn a minor foothold into a major compromise.
Active Directory (AD) is the heart of most corporate networks, but its permissions can become a tangled “rat’s nest” of complexity. An automated vulnerability scanner can’t understand the intricate web of trust relationships that a human attacker can exploit.
The Flaw: A standard user account may seem harmless, but it could have a hidden, indirect path to administrative power. It’s not uncommon to find that the default “Domain Users” group has overly broad permissions, such as the ability to log into nearly every computer on the network, including servers.
Specifically, we look for the “GenericAll” permission. This allows one group to fully control another object. Even if the target account is disabled, an attacker with GenericAll rights can enable it and abuse those permissions.
The Attack: As we acquire user accounts, we use Bloodhound to map complex relationships and find unexpected privilege escalation paths.
This exact flaw was enumerated on a recent pentest where the “Domain Users” group had GenericAll access to a disabled service account. Seemingly for no reason, this permission existed on an account no one was monitoring.
From there, we enabled the account, reset the password, and masqueraded as that service account on the network. We discovered this service account had interesting permissions, including the ability to modify the password of a Domain Administrator.
After confirming this action was allowed within the Rules of Engagement (ROE), the team abused these permissions to take over the entire AD forest and ultimately the network.
The Result: By manually navigating this maze, we can turn a low-privilege account into a full Domain Administrator, demonstrating a critical risk that no vulnerability scanner would discover.
Mitigation Strategies: Active Directory is a common target because it’s often a “rat’s nest” of complex permissions.
The most damaging breaches rarely rely on a single vulnerability. Instead, they emerge from creative chaining of minor, overlooked issues, a forgotten file, an exposed port, a default password—into a pathway through the maze of internal trust.
Key Takeaways:
Defending against these threats requires adopting the attacker’s perspective. This is where red team expertise provides the greatest value, simulating real-world thinking, not just automated scans.
Your security journey doesn’t end with this playbook. Contact us to learn how our expert-led penetration testing helps organizations secure their networks from the inside out.
That wraps up The Attacker’s Playbook. But your security journey shouldn’t stop here. Check out our deeper dives on Active Directory in “Abusing Active Directory: Down the Rabbit Hole We Go,” and watch this short clip from our recent webinar on Active Directory permission risks — or get in touch to test your defenses before attackers do.
