What are the most dangerous Active Directory misconfigurations and how can they be prevented?

Active Directory (AD) is the backbone of identity and access management in most organizations. But when not configured properly, it becomes a hacker's playground. From unauthorized access to complete domain compromise, attackers often exploit simple misconfigurations. In this blog, we'll explore the six most dangerous Active Directory misconfigurations, how these attacks work, and practical tools and tips to prevent them.

What Is Active Directory and Why Is It Targeted?

Active Directory is a Microsoft service used to manage users, groups, permissions, and computers in a network. Because it controls access to everything—from files to applications—it's a high-value target for cybercriminals.

Once attackers gain access to AD, they can escalate privileges, move laterally, and deploy malware, ransomware, or steal data undetected.

Top 6 Dangerous Active Directory Misconfigurations

Let’s break down each major misconfiguration, how it's abused, and how you can stop it:

1. Kerberoasting

What it is: Attackers request service tickets (TGS) from the domain controller and crack them offline to get passwords of service accounts.

How it works:

• Uses legitimate Kerberos ticket requests.

• Targets accounts with weak passwords and Service Principal Names (SPNs).

  
  

Prevention:

• Use long, complex passwords or Group Managed Service Accounts (gMSAs).

• Monitor Event ID 4769 for unusual TGS requests.

• Avoid using privileged accounts as service accounts.

2. AS-REP Roasting

What it is: Exploits accounts that have “Do not require Kerberos preauthentication” enabled, allowing attackers to retrieve password hashes offline.

How it works:

• Bypasses preauthentication to receive encrypted ticket-granting tickets (TGTs).

• Cracked using offline brute-force tools.

Prevention:

• Disable "Do not require preauthentication" on all accounts.

• Enforce strong password policies.

• Watch for Event ID 4768 activity.

3. LLMNR & NetBIOS Poisoning

What it is: Exploits fallback name resolution protocols to trick computers into sending credentials to a fake device.

How it works:

• When DNS fails, systems broadcast requests over LLMNR or NetBIOS.

• Attackers respond with a spoofed answer and steal NTLM hashes.

Prevention:

• Disable LLMNR and NetBIOS over TCP/IP.

• Use DNS-only name resolution.

• Implement SMB signing.

4. NTLM Relay Attacks

What it is: Uses stolen NTLM credentials to authenticate to other services without knowing the actual password.

How it works:

• Captures NTLM hashes from services like SMB.

• Relays the hash to another machine to gain access.

Prevention:

• Enforce SMB signing and disable NTLM where possible.

• Implement strict firewall rules to limit lateral movement.

• Use LDAP signing and channel binding.

5. NTDS.DIT Dumping

What it is: Attackers dump the NTDS.dit file that stores all domain user hashes.

How it works:

• Requires admin-level access.

• Dumps and extracts credentials using tools like Mimikatz or secretsdump.py.

Prevention:

• Limit access to Domain Controllers.

• Regularly audit Backup Operators and Domain Admins.

• Monitor for unusual use of VSSAdmin, ntdsutil, and large file transfers.

6. Misconfigured Group Policies (GPOs)

What it is: Poorly configured Group Policy Objects can allow unauthorized privilege escalation.

How it works:

• Incorrect permissions on GPOs let users modify them.

• Can lead to domain-wide control or malware persistence.

Prevention:

• Regularly audit GPOs using Microsoft Security Compliance Toolkit.

• Ensure only trusted administrators can edit GPOs.

• Apply least-privilege access models.

 Attacks vs. Prevention

Tools to Detect and Prevent Active Directory Misconfigurations

Here are some popular tools every SOC analyst and system admin should know:

Why These Misconfigurations Are So Dangerous

These vulnerabilities don’t require advanced malware or ransomware—they simply exploit bad configuration hygiene. Because most organizations trust AD as a secure source of truth, a single mistake can lead to:

• Lateral movement

• Privilege escalation

• Credential theft

• Complete domain compromise

Conclusion

Cyber attackers thrive on misconfigurations and weak defaults. These six issues are not just theoretical—they are being exploited right now in real-world attacks.

By identifying and remediating them, organizations can:

• Harden their AD environment.

• Reduce the attack surface.

• Stop attackers before they escalate.

Stay secure. Audit often. Fix misconfigs before attackers find them.

FAQs

What is Kerberoasting in Active Directory?

Kerberoasting is an attack that targets service accounts by requesting encrypted Kerberos tickets and cracking them offline to extract passwords.

How can I prevent AS-REP Roasting attacks?

Disable the “Do not require Kerberos preauthentication” setting and enforce strong password policies on all accounts.

What is LLMNR Poisoning and why is it risky?

LLMNR Poisoning exploits fallback name resolution protocols to trick systems into revealing NTLM hashes, allowing credential theft.

How do attackers perform NTLM Relay Attacks?

Attackers capture NTLM authentication requests and relay them to other systems to gain unauthorized access without knowing passwords.

What is NTDS dumping?

NTDS dumping involves extracting the NTDS.dit file from a Domain Controller, which contains all domain password hashes.

Why are misconfigured Group Policies dangerous?

Improper GPO configurations can allow low-privilege users to modify policies and escalate privileges or introduce malware.

What tools can detect Active Directory misconfigurations?

Popular tools include BloodHound, PingCastle, Purple Knight, GPOZaurr, and Microsoft's LAPS for securing local admin passwords.

How do I protect my AD environment from Kerberoasting?

Use long, complex passwords for service accounts and monitor unusual ticket-granting service (TGS) requests.

Can LLMNR and NetBIOS be disabled safely?

Yes, most modern networks do not need LLMNR or NetBIOS, and disabling them reduces the risk of poisoning attacks.

What is a secure alternative to NTLM authentication?

Kerberos is the preferred secure alternative to NTLM in Windows environments.

How often should I audit GPOs in Active Directory?

Regularly—ideally monthly—to ensure only authorized administrators have GPO modification rights.

What are common signs of NTDS dumping?

Unexpected use of backup tools, large file transfers from domain controllers, or the presence of known password dumping tools.

How does BloodHound help with AD security?

BloodHound maps relationships and permissions in AD, helping identify potential paths for privilege escalation.

What is the purpose of Purple Knight?

Purple Knight scans Active Directory for common vulnerabilities and misconfigurations with remediation suggestions.

How does PingCastle differ from BloodHound?

PingCastle provides an executive-style security risk score for AD, while BloodHound is more focused on attack paths.

What is the role of SMB signing in preventing relay attacks?

SMB signing prevents tampering by requiring a cryptographic signature, stopping unauthorized relayed traffic.

Why should NTLM be disabled?

NTLM is outdated and vulnerable to relay attacks and pass-the-hash attacks; it should be replaced with Kerberos.

How do I detect AS-REP Roasting attempts?

Monitor for Event ID 4768 and analyze for accounts with preauthentication disabled.

What is the GPOZaurr tool used for?

GPOZaurr helps audit and manage Group Policy settings, ensuring secure configurations across your AD environment.

Can attackers exploit default AD configurations?

Yes, many attacks succeed due to default settings like insecure GPOs, weak service account passwords, or unmonitored privileges.

Are service accounts a common target in AD attacks?

Yes, service accounts often have elevated privileges and weak passwords, making them prime targets.

What does the NTDS.dit file contain?

NTDS.dit stores all user and password data for a domain; compromising it gives attackers complete access.

How to secure the Domain Controller?

Restrict physical and remote access, limit admin accounts, apply updates, and monitor logs continuously.

How do attackers find misconfigurations in AD?

They use tools like BloodHound, PowerView, or manual enumeration via PowerShell and LDAP queries.

Why are Group Managed Service Accounts (gMSAs) better?

gMSAs automatically manage complex passwords for service accounts and are harder to crack.

What event logs should I monitor for AD attacks?

Key logs include Event IDs 4624, 4768, 4769, and 4672 for logins, Kerberos activity, and privilege escalations.

How can LAPS enhance AD security?

LAPS manages local admin passwords automatically, making it difficult for attackers to reuse credentials.

What is a least privilege model in AD?

It ensures users only have the minimum access needed for their role, reducing the attack surface.

Can attackers escalate privileges using GPOs?

Yes, misconfigured GPOs can be modified to add users to privileged groups or run malicious scripts.

Should I separate admin and user accounts?

Yes, using dedicated admin accounts reduces the risk of attackers compromising privileged credentials during phishing or malware attacks.

How do I start hardening Active Directory today?

Begin by auditing existing configurations, implementing strong password policies, disabling legacy protocols, and using security tools like PingCastle and BloodHound.