Building a Hardened AD Environment in the Age of Hybrid Cloud

More than 90% of organizations will adopt hybrid cloud setups by 2027. This means that many still depend on on-premises Active Directory (AD) while also using services like Azure AD. It’s a flexible model, but it also increases risk. Attackers no longer need to breach your network physically. They can find their way in through misconfigurations, weak credentials, or exposed services.

Many businesses have not adjusted their AD security to meet these new threats. Older AD setups were built with the idea that everything stayed inside the network. That’s no longer true. Once attackers get in, they often go straight for AD. They know it controls access to nearly every system and service. And if they exploit it, they can move fast and deep.

This article offers a clear guide to strengthening your AD environment. It will help you identify weak points, apply practical changes, and make your setup more secure—whether it’s on-prem, cloud-connected, or fully hybrid.

1. Watching for Strange Kerberos Activity

Kerberos is a trusted part of AD, but it can be abused. One of the most common tricks is called Kerberoasting. This attack happens when someone requests service tickets for accounts with weak passwords. They can then try to crack those tickets offline to gain access.

To defend against this, you should keep an eye on Kerberos ticket requests. Watch for patterns like large numbers of requests in a short time or requests made at strange hours. These signs often point to malicious activity.

Strong monitoring can help you detect early warning signs. You should also apply specific protection against Kerberoasting attack techniques, such as enforcing strong passwords on service accounts and limiting ticket lifetime. These small changes make it much harder for attackers to succeed.

2. Setting Strong Password Rules for Service Accounts

Service accounts often run in the background, supporting apps and services. But many of them still use weak passwords. That makes them easy targets for Kerberoasting and other attacks.

You should require long, complex passwords for all service accounts. Better yet, use group-managed service accounts (gMSAs) where possible. These accounts handle password rotation automatically, which lowers the chance of human error.

Also, avoid using one service account across multiple services. If one account gets exposed, the damage will spread much faster. Keeping accounts separate limits the fallout.

3. Separating Critical Systems with Tiering

Network segmentation, or tiering, means dividing systems based on their risk level. For example, domain controllers should sit in their own protected tier. Workstations and regular user systems belong in a different tier.

This separation keeps attacks from spreading too quickly. If someone compromises a user account, they won’t be able to move straight to critical servers. Instead, they’ll face more security checks and limitations.

Tiering also makes it easier to monitor key systems. You can set up different rules and alerts for each tier. That way, you’re not flooded with unnecessary data when reviewing logs or looking for threats.

4. Limit Privilege with Just-in-Time Access

Always-on admin rights create serious security risks. If an attacker compromises an account with constant elevated access, they can cause widespread damage quickly. That’s why just-in-time (JIT) access is important.

JIT gives users admin rights only when they need them. These rights expire after a short time. This limits the chances of misuse. It also reduces the number of high-level credentials available at any given time.

Several tools, including Microsoft’s Privileged Access Management (PAM), make JIT easier to manage. You can set approvals, track usage, and even trigger alerts. The goal is to give the right access to the right person for the right amount of time—and no more.

5. Make Logging and Detection a Priority

You can’t protect what you can’t see. That’s why logging and detection must be part of your AD hardening plan. Many attacks leave traces—if you’re collecting the right data.

Start with the basics. Enable advanced security audit policies for authentication, directory service access, and account logon. Capture logs for Kerberos activity, LDAP queries, and PowerShell usage. These areas often show early signs of attack.

Send your logs to a centralized system like a SIEM. There, you can search for and alert people about suspicious behavior. Watch for actions like repeated failed logons, unusual ticket requests, or privilege escalations. With solid detection in place, you get more time to respond and stop an attack before it spreads.

6. Keep Systems Patched and Up to Date

Outdated systems are one of the easiest ways in for attackers. A known AD exploit with a public fix is still a threat if the patch hasn’t been applied. That’s why patching should never be skipped.

Focus on domain controllers, AD-connected servers, and high-privilege systems. Make sure you’re applying both OS and software updates. Where possible, test patches in a staging environment first. This helps avoid downtime.

Create a regular patch schedule and stick to it. If you fall behind, attackers will find and use those gaps. Staying current isn’t exciting, but it is essential.

7. Lock Down Azure AD Connect

Azure AD Connect is what bridges your on-prem and cloud environments. If it’s not secured, it becomes a weak spot. Attackers who get into this tool can steal credentials or change sync rules. That opens the door to much bigger problems.

To prevent that, protect the AD Connect server like you would a domain controller. Restrict who can log in. Remove internet access if it’s not needed. Use strong authentication and monitor all changes.

You should also watch for suspicious sync activity. If new objects are syncing unexpectedly, something could be wrong. Treat this system with extra care. It holds the keys to both sides of your hybrid setup.

8. Review Settings and Train Your Team

Technology alone won’t keep AD safe. Your team needs to understand what to look for and how to act. That means ongoing training and regular reviews.

Hold short training sessions for IT staff. Walk through recent attack methods and show how they work. Teach them to spot warning signs and how to respond. This builds awareness and confidence.

You should also audit your AD setup regularly. Check for inactive accounts, open ports, and policy changes. Don’t assume things are fine—verify it. A well-trained team and a tight review process go a long way in preventing mistakes and spotting risks early.

As more organizations move toward hybrid cloud, the need to protect Active Directory grows stronger. AD is still the backbone of most identity systems, and it remains a top target. Hardening your environment doesn’t require a full rebuild. It requires smart, focused steps that lower risk.

By tightening access, monitoring activity, keeping systems updated, and training your team, you create a stronger line of defense. These actions won’t just protect you from today’s threats. They’ll help you stay ready for what comes next.

A secure AD is not a one-time task. It’s an ongoing process—but one worth doing right.