Active Directory Penetration Testing Methodology

🛡️ Active Directory Penetration Testing Protocol #

Subject: Active Directory Attack Path Simulation & Security Audit
Location: Bristol, United Kingdom
Entity: Cyber Sentinel Solutions Ltd (CSSLTD)
Status: Operational Framework v3.1

As Cyber Sentinel Solutions Ltd, we have engineered a professional, step-by-step methodology for Active Directory (AD) penetration testing. This scenario relies on advanced open-source software, primarily BloodyAD (operating directly via LDAP and SAMR protocols without relying on native Windows tooling) and the Impacket suite.

This protocol ensures rigorous security verification, allowing our engineers to map and execute attack paths—from initial reconnaissance to full domain compromise—while maintaining operational stealth.

🔬 Step 1: Enumeration & Reconnaissance #

The engagement begins with mapping the domain structure. Complete visibility is the foundation of any successful AD exploitation.

  • Device & User Enumeration: We extract the complete list of computer objects (to identify Domain Controllers, critical servers, and workstations) and user accounts to build our target database.
  • Container & OU Analysis: We analyze Organizational Units (OUs) to understand the network topology and determine where Group Policy Objects (GPOs) are applied.
  • DNS Zone Dumping: We extract internal DNS records. This reveals hidden hosts, subnets, and legacy infrastructure that may not be visible through standard AD LDAP queries.
  • Group Membership Validation: We verify user group memberships and extract the member lists of high-value targets, specifically targeting groups like Domain Admins, Enterprise Admins, and Backup Operators.

⚙️ Step 2: Configuration & Account Vulnerability Analysis #

In this phase, we hunt for misconfigurations, human errors, and risky default settings inherent to Windows environments.

  • Deep Object Inspection: We query all LDAP attributes of high-value accounts. We actively hunt for cleartext passwords stored in custom attributes (e.g., unixUserPassword, userPassword, or Description) and analyze AdminSDHolder protections.
  • Machine Account Quota (MAQ) Verification: We evaluate the ms-DS-MachineAccountQuota attribute. By default, this is set to 10, allowing any authenticated user to join up to 10 new machine accounts to the domain. This is a critical vector frequently leveraged in privilege escalation and Resource-Based Constrained Delegation (RBCD) attacks.
  • User Account Control (UAC) Manipulation: We test the ability to modify UAC flags on subordinate accounts (e.g., toggling the ACCOUNTDISABLE flag to lock or unlock targeted users as a proof of concept).

🔑 Step 3: Authentication Attacks #

We exploit weaknesses within the Kerberos protocol. These attacks do not require administrative privileges, only a standard authenticated session.

  • Kerberoasting: We map accounts possessing a configured Service Principal Name (SPN). If a service is mapped to a user account, we request a Ticket Granting Service (TGS) ticket for that SPN and extract it from memory. The ticket is then cracked offline to recover the plaintext password.
  • AS-REP Roasting: We hunt for accounts explicitly configured with Kerberos pre-authentication disabled (the DONT_REQ_PREAUTH flag). Using tools like impacket-GetNPUsers, we retrieve the AS-REP hash directly from the Key Distribution Center (KDC) and crack it offline, requiring zero knowledge of the target’s current password.

🚪 Step 4: Access Control List (ACL) Abuse #

When misconfigured DACLs/SACLs are identified, we weaponize them for vertical privilege escalation.

  • Force Password Reset: If a compromised low-privileged account holds the ForceChangePassword right over a higher-tier user, we forcefully change the victim’s password to a known value, completely hijacking the target account.
  • GenericAll / WriteDacl Abuse: If the audited account possesses full control (GenericAll) over the Domain Admins group, our operators can directly inject their own low-privileged account into the Domain Admins group, achieving instant maximum privilege escalation.

💥 Step 5: Domain Compromise & Hash Extraction #

Upon securing sufficient privileges, we test the domain’s resilience against advanced extraction and persistence techniques.

  • DCSync Attack: We simulate the behavior of a legitimate Domain Controller using the Directory Replication Service (DRS) protocol. By granting an account DS-Replication-Get-Changes-All rights, we execute impacket-secretsdump to remotely dump the entire NTDS.dit credential database, including Kerberos keys and the krbtgt hash.
  • LAPS Password Extraction: We verify unauthorized read access to the ms-Mcs-AdmPwd attribute. Extracting standardized Local Administrator Password Solution (LAPS) passwords enables immediate lateral movement across all domain workstations.
  • Shadow Credentials Attack: If we possess write privileges over a target object (e.g., a Domain Controller), we inject a malicious cryptographic certificate into the msDS-KeyCredentialLink attribute. This allows us to request a TGT acting as that machine, bypassing traditional password authentication entirely.
  • Resource-Based Constrained Delegation (RBCD): We create a rogue computer account in the domain and modify the msDS-AllowedToActOnBehalfOfOtherIdentity attribute on the target Domain Controller. We then generate a forged TGT via impacket-getST and seamlessly log into the target DC as the Administrator user via impacket-psexec.

🧹 Step 6: Environmental Cleanup #

As a professional security consultancy, CSSLTD ensures absolute environmental sterility post-engagement. Every privilege granted during the test—such as rogue accounts, modified ACLs, added group memberships, or DCSync rights—is systematically revoked to guarantee the environment is not left vulnerable to external threat actors.

📊 Step 7: Strategic Recommendations & Reporting #

The final artifact provides actionable, architecturally sound defensive strategies to mitigate the identified attack paths:

  1. Restrict Machine Account Creation: Immediately reduce the ms-DS-MachineAccountQuota attribute from the default 10 to 0 for standard users to neutralize RBCD attacks.
  2. Attribute Hardening: Implement strict policies against storing passwords or sensitive data in LDAP attributes like Description or userPassword.
  3. Kerberos Hardening: Mitigate Kerberoasting and AS-REP Roasting by enforcing highly complex passwords for service accounts (minimum 25 characters), mandating Kerberos Pre-Authentication globally, and purging unused SPNs.
  4. Architectural Hardening:
    • Deploy Microsoft’s Tiered AD Administration Model to prevent credential crossover.
    • Enforce the use of the Protected Users security group for all administrative accounts.
    • Integrate continuous AD auditing using tools like BloodHound CE to detect emerging attack paths before they are exploited.
    • Implement rigorous SIEM monitoring for LDAP anomalies, specifically alerting on DCSync replication requests (Event ID 4662) and suspicious Kerberos ticket operations (Event ID 4769).
# AUDIT SIGN-OFF
[+] Status: COMPLETE
[+] Methodology: CSSLTD-AD-PENTEST-v3.1
[+] Tools Used: BloodyAD, Impacket Suite