Active Directory Hardening can control your security outcomes and influence who gets access to data. When you deploy servers in their default states, security is often neglected. Although out-of-the-box servers are ready-to-use, they are not safe. By putting a little time into your security organizations, you can make a significant difference in how your users are protected. This guide covers everything you need to know about the Active Directory Hardening Checklist.
Active Directory Hardening Checklist
Active Directory (AD) is a Microsoft-developed system that manages user access to an organization’s computers and networks. It’s also a common target for cyberattacks. The process for properly configuring and securing this system is called Active Directory hardening.
The following Active Directory hardening checklist helps organizations minimize their attack surface and effectively deal with cyber threats. Key strategies include least privileged access review, regular permission allocation check, secure authentication, and configuration management of your domain controllers.
Least Privileged Access
Reducing the use of overly permissive access rights and following the least privilege principle should be a must in AD security. This principle states that the end users of systems should have only as much access to perform their job functions.
To do this, companies will need to start by identifying all accounts that have administrative rights and reassess which ones are required. Administrative accounts need to be isolated from normal user space using different logins. Moreover, using Role-Based Access Control (RBAC) assignments can simplify the permission assignment on designated roles within the organization.
Regularly Audit Permissions
It is crucial to the security of Active Directory that permissions are audited regularly. Companies should run permission audits in order to look at the current permissions, for instance, user accounts and their group memberships, as well as access rights, so that only authorized users have the right permissions.
Organizations also need to conduct regular audits, not just of account holders accessing your organization’s data but also a follow-up on the administrative actions. For example, this can be checking the logs for changes by those with elevated rights and so on. Organizations can detect possible fraudulent behavior early enough to mitigate risks by monitoring administrative activity.
Ensure Secure Authentication
Secure authentication mechanisms are fundamental to the protection of Active Directory. One way to go about this is by ensuring Multi-Factor Authentication (MFA) for all users, especially admins. MFA requires two or more forms of identity verification to access a user´s accounts, which creates an added layer of security. Apart from MFA, companies should have a good password enforcement policy.
Businesses may also want to enforce account lockout policies to protect against brute-forcing. Brute force users to elongate the strength of their passwords and set thresholds for failed login attempts, which can lock accounts temporarily (blocking out hackers who attempt to access an account by spinning through a list of potential password guesses). Of course, this must be tempered against the need, not inadvertently locking legitimate users out.
Secure Domain Controllers
Domain Controllers (DCs) are important in Active Directory and have to be supported with a larger protective barrier. It should be a top priority to minimize the number of people who physically enter DCs, and organizations must make it apparent that the servers in question are within those specific data centers. The secure perimeter puts physical, administrative, and technical controls in place, including surveillance systems whereby the data can be utilized for monitoring availability, which acts as access control.
Regularly updating DCs with security patches is also important to help guard against vulnerabilities. Large patches and updates that would address these vulnerabilities should be well-tested before implementation, but the testing takes time, so it is recommended to manage this with a robust patch management process.
Network Segmentation
One important way to improve security with Active Directory is network segmentation. Organizations can also further reduce the attack surface and prevent any lateral movement by isolating domain controllers as critical systems. In the case of on-premises networks, Virtual Local Area Networks (VLANs) can be used to delineate segments in the network and allow only trusted entities to access domain controllers.
Firewalls are necessary to prevent traffic between various network segments. Firewall logs should always be checked to detect any suspicious activity or unauthorized access, prompting the necessary measures.
Also, the use of micro-segmentation technology is highly recommended because it allows an organization greater precision in how traffic flows are defined on that same network. Doing so lets you apply security policies down to a granular level, working for more accurate mappings of which systems connect with one another.
Monitoring and Logging
Detecting and responding to potential security incidents in Active Directory is very essential which is why you need good monitoring/logging. Organizations can ensure complete monitoring by enabling detailed logging for all AD events, including login/logoff activities and changes to accounts or group memberships.
Additionally, security information and event management (SIEM) solutions can be incorporated to improve monitoring by aggregating logs from AD and other systems for analysis, allowing correlation. The capability for real-time threat detection, where it spots something fishy and alerts the company to respond in a proactive mode.
Group Policy Configuration
Group Policies are a very powerful way to enforce security settings across the entire AD enterprise. Organizational settings should be implemented through GPOs to apply security baselines that match the organization’s policies.
For instance, GPOs could be utilized to enforce password complexity requirements, account lockout policies, and software restrictions. It is also important to regularly review and update GPOs, as they can become stale over time or even conflict with other policies. GPO audits keep compliance with security standards and detect misconfiguration that may be adding risk to the environment.
Monitoring Active Directory Security
As with any other process, monitoring the Active Directory demands consistency and versatility. The AD hardening checklist can assist in mitigating risks and enhancing the security of your systems, thereby making them more robust.
To get a free demo of how you can improve Active Directory security, contact SentinelOne today. Discover how our innovative AI-based products, such as the Singularity™ platform can make the process easier, enhance your control, and defend your business against new and emerging threats.
Conclusion
Active Directory security may be an iterative process but it works. Don’t deviate from established baselines, and prioritize your users and assets. Focus on our Active Directory hardening checklist items to stay on track. If you need help. you can reach out to SentinelOne for further assistance.
Active Directory Hardening Checklist FAQs
The Active Directory Hardening Checklist is a step-by-step guide for locking down AD. It covers reviewing admin accounts, enforcing least privileged access, securing domain controllers, configuring group policies for password and lockout rules, segmenting networks, and setting up monitoring and logging.
You work through each item to reduce exposed services, enforce secure configurations, and keep your AD environment under tight control.
AD sits at the heart of user and device access. If it’s weak, attackers can steal credentials, move laterally, or seize control of critical systems. Hardening AD closes common gaps—like default settings or over-privileged accounts—so threats can’t exploit them. This lowers breach impact, cuts cleanup time, and keeps the business running without surprise outages or data loss.
Least Privileged Access means giving each account only the exact rights needed to do its job—no extras. You identify all admins and service accounts, then trim or isolate those with broad rights. Using role-based assignments, you group and assign permissions so nobody can wander beyond their needed scope. This shrinks your attack surface and stops compromised accounts from doing too much damage.
You enable detailed logging for key events—logons, group-membership changes, config edits—and feed those logs into a SIEM. That system watches for unusual patterns (like mass account creations or wrong-time logins) and alerts you in real time. Regular audit reports and permission-change reviews help spot odd behavior before it becomes a full breach.
Beyond the core items, keep service accounts on rotating strong passwords, disable legacy protocols (SMBv1), enforce secure admin workstations for high-privilege tasks, and review GPOs to weed out stale or conflicting settings. Run frequent vulnerability scans on DCs and connected systems, and hold quarterly tabletop exercises to validate incident-response plans.
Segmenting your network isolates domain controllers and admin tools on dedicated VLANs or firewalled zones. That way, even if a workstation is hacked, attackers can’t easily jump to critical AD hosts. Micro-segmentation lets you lock down traffic at the workload level, so only approved systems talk to each other—stopping lateral movement in its tracks.
Monitoring and logging are your eyes on AD. Detailed event logs capture every logon, policy change, and permission update. A centralized SIEM correlates those logs, flags anomalies, and keeps an audit trail for investigations. Without real-time alerts and stored logs, you’d miss stealthy intrusions and lack evidence to respond quickly.
No. AD security is ongoing. Threats evolve, staff roles change, and software gets patched. You need regular audits of permissions, GPOs, and network segments. Update your checklist items when new attacks surface or Microsoft issues guidance. Treat hardening as a living process, not a one-off project.
SentinelOne’s Singularity™ platform brings AI-driven detection, real-time policy enforcement, and automated remediation to AD environments. It monitors AD events, spots misconfigurations, enforces MFA and secure admin host use, and integrates with your SIEM.
With one-click fixes, you can quarantine suspect activities, roll back unwanted changes, and keep AD settings aligned with your hardening checklist.