Ways to Strengthen Active Directory Security

Active Directory (AD) is a powerful tool. It manages user access, resources, and authentication across networks. But with great power comes great risk. If attackers gain control, they can access everything—files, accounts, systems. That’s why securing Active Directory is critical for any organization.

Weak AD configurations are a goldmine for hackers. Many successful breaches start with poor password policies or excess privileges. So what can you do? Let’s break down practical and proven ways to strengthen Active Directory security today.

Maintain a Minimal Number of Privileged Users

Too many cooks spoil the broth—and the same goes for admin privileges. Giving everyone Domain Admin access is like handing out master keys. It increases your attack surface and risk of credential theft.

Stick to the least-privilege model. Only assign admin rights when absolutely necessary. Review these accounts often. Remove users who no longer need elevated access. Don’t let old projects or inactive users retain special privileges.

Microsoft recommends using separate accounts for administrative duties. This minimizes risk during daily operations. Admins shouldn't browse the web or check email with their privileged accounts. That’s just asking for trouble.

Privileged users should also log in only from secure administrative hosts. Not from regular workstations or personal devices. A compromised endpoint can lead to a full domain compromise.

Use Groups to Assign Privileges

Organizing access through groups is smarter than assigning rights directly. It’s easier to manage, review, and audit. It also helps avoid messy permission trails.

Group Policy Objects (GPOs) allow you to apply policies consistently. Create security groups based on roles—like Helpdesk, Server Admins, or HR. Assign privileges to these groups, not individuals.

Then add or remove users as needed. This keeps your environment clean and controlled. It also limits the chance of human error during permission changes.

Avoid adding users to powerful groups like Domain Admins unless absolutely required. Review group memberships regularly. Watch out for nested groups that may inherit dangerous permissions unintentionally.

Group-based access helps enforce consistent privilege management. It aligns with compliance standards and makes your audits a lot smoother.

Secure Accounts with Administrator Privileges

Admin accounts need ironclad protection. These accounts have broad control and are often targeted by attackers. A weak link here can lead to a complete network breach.

Start by renaming the default Administrator account. Attackers often look for this first. Disable it if possible, or restrict its use.

Use complex, unique passwords for each admin account. Consider multi-factor authentication (MFA) to add an extra layer. Enable account lockouts after multiple failed attempts.

Log all admin activities. Monitor sign-ins and access logs. If an admin logs in at 3 a.m. from another country, something’s wrong. Respond fast.

Implement Just-In-Time (JIT) access tools. This gives temporary admin rights instead of full-time access. It's safer and aligns with zero-trust principles.

Enforce Modern Password Policies

Old password rules don’t cut it anymore. For years, IT departments forced users to change passwords every 30 days. Users responded by choosing simple variations—like “Spring2024!” or “Admin123!”

Modern password policy emphasizes complexity over frequent changes. Use longer passphrases instead of short, complex strings. A phrase like “Coffee&Rain@5AM!” is easier to remember and harder to crack.

Use Group Policy to enforce these rules across the domain. Set minimum password lengths. Require a mix of uppercase, lowercase, numbers, and special characters. Ban commonly used passwords using a password blacklist.

Avoid forcing password resets every month. Instead, focus on stronger passwords and educating users. A secure password changed yearly is often better than a weak one changed monthly.

Enforce Strong Passwords on Service Accounts

Service accounts are often overlooked—but they pose serious risks. These accounts run automated tasks, backup jobs, or applications. They usually have high privileges. And they rarely rotate passwords.

Attackers love service accounts. Why? Because their credentials are stored in scripts, config files, or scheduled tasks. If those passwords are weak or never change, it’s game over.

Use managed service accounts when possible. These automatically manage passwords. If that's not feasible, store passwords in a secure vault. Rotate them regularly.

Don’t let service accounts have interactive login rights. They shouldn't be used to sign in manually. Disable this unless absolutely necessary.

Also, audit what each service account can access. Don’t give them full domain control if they only need access to one server.

Conduct Regular Assessments to Detect Password Policy Violations

You can't fix what you don’t measure. Regularly check if users and accounts are complying with password policies. Look for weak or stale passwords.

Use tools like Microsoft’s Local Administrator Password Solution (LAPS) or third-party tools like Purple Knight. These scan your AD environment and flag issues.

Create reports to show accounts with passwords older than 90 days. Flag accounts using default or common passwords. Investigate dormant accounts that haven’t been used in months.

Assessments should be scheduled—not just done once a year. Make it a monthly or quarterly habit. This helps you stay ahead of threats and maintain compliance.

And don’t forget to test your password policy itself. Try logging in with banned passwords or short phrases. Make sure the system enforces your rules.

Turn Off the Print Spooler Service

This may sound odd—but the Print Spooler service is a known attack vector. Especially on Domain Controllers. It allows attackers to execute remote code or move laterally through the network.

Unless you're printing directly from a domain controller, turn it off. You won’t miss it. Use PowerShell or Group Policy to disable the Print Spooler.

Make this part of your baseline server hardening checklist. It’s a simple fix that closes a dangerous door.

If printing is essential on some machines, restrict access. Apply Group Policy settings to limit who can use the spooler and where it can connect.

Disable SMBv1 and Restrict NTLM

Outdated protocols are like open windows during a storm. SMBv1 and NTLM are two of the biggest offenders. They were designed in the ‘90s—long before ransomware or credential theft became daily threats.

Start by disabling SMBv1 entirely. It's insecure and unsupported. Most modern operating systems no longer need it. Use PowerShell or Group Policy to remove it.

Next, limit or block NTLM authentication. Encourage Kerberos instead. NTLM is susceptible to relay attacks and hash theft.

Check your environment for systems still using NTLM. Replace them or reconfigure authentication methods. Use security logging to catch NTLM attempts.

Restricting outdated protocols cuts off common hacker paths. It's one of the fastest ways to reduce your attack surface.

Conclusion

Securing Active Directory isn’t optional—it’s vital. Every day, attackers probe networks looking for misconfigurations, outdated protocols, or weak passwords. Don't let them find an open door.

Start by limiting privileged accounts. Assign permissions through groups, not individuals. Protect admin credentials like they're crown jewels. Enforce modern password policies and rotate service account passwords.

Run regular assessments and fix what’s broken. Disable legacy services like Print Spooler and SMBv1. Restrict NTLM wherever possible.

A secure Active Directory makes your entire organization safer. It reduces risk, simplifies audits, and builds trust. The steps are clear. Now it’s your move.

Want to see where your AD security stands today? Run a free security scan. You might be surprised by what turns up.