Active Directory (AD) is a hierarchical directory service that enables you to manage users, groups, access control, and policy administration. AD is used to secure network resources, user accounts, and data across a variety of applications and services for organizations of all sizes.
Maintaining AD is like tending a garden. Weeds need to be pulled and plants should be pruned. Similarly, processes and procedures should be in place to clean up AD by deleting users, computers, and other objects in the directory that are no longer used.
Benefits of Regular AD Cleanup
Maintaining a clean AD plays an important role in a company’s overall security program. It helps to reduce the risk of unauthorized access and potential security breaches and can also improve authentication and replication performance.
Enhanced Security
A lack of upkeep in AD can obscure insights into the effectiveness of applied permissions and access controls, which can lead to unknown vulnerabilities. AD cleanup enhances security by removing inactive users and stale computer objects. Attackers can exploit inactive user accounts that still have access to the network to gain unauthorized access or escalate privileges.
Performance
In an AD environment, the removal of inactive objects and out-of-date directory metadata helps to optimize overall performance. A clean and up-to-date AD provides faster Lightweight Directory Access Protocol (LDAP) search results, quicker authentication, and efficient processing of Group Policy Objects (GPOs) during logon.
Removing obsolete objects also helps minimize the size of the AD database (NTDS.dit—NT Directory Services Directory Information Tree). Managing the growth and size of the DIT helps with LDAP performance, replication, and promoting new domain controllers that must synchronize with the directory before they can come online.
Authentication and replication performance also increases when sites and subnets are up to date and reflect the physical and logical network. AD uses network topology information defined in sites and subnets to build its replication topology. Inaccurate or missing subnet definitions can result in users and computers authenticating to domain controllers in suboptimal locations, which can increase logon time.
Compliance and Audit Readiness
Accurate user data in AD is crucial to meeting compliance standards. Regular maintenance coupled with well-understood and documented policies can facilitate a much smoother audit process. For example, an account that remains active with access to critical systems after a user has been terminated will typically lead to high-risk findings in most audits.
Cost Savings
The upfront cost of cleaning up AD and putting in processes and automation to maintain a clean AD will pay your organization back in dividends. While a clean AD will be more performant and efficient, the real benefit is in the overall reduction of operational overhead. The automation of processes such as user creation, updates, and terminations not only improves security but also enables IT administrators to allocate their time and expertise to tasks that have a more significant impact on business operations.
How to Clean Up AD
Cleaning up AD is a process that demands careful planning and structured execution. When developing the scope of an AD clean-up project, the following factors should be considered.
Conduct a Comprehensive Inventory
The first step of any security initiative should be to gain an understanding of what is being secured. For AD, that means inventorying all AD objects. This includes examining every AD user, computer and group object to identify stale accounts and unnecessary data. After these objects are identified, develop processes and policies to manage and remove stale objects.
Automate User Lifecycle Management
Incorporate automated processes for provisioning and deprovisioning accounts in AD. Ideally, all user accounts should be sourced from an HR system that maintains user data and is the system of record for users in an organization. One option for automatic provisioning is Microsoft’s Entra Provisioning Service. Any accounts that are not sourced from an HR system, such as service accounts or accounts for temporary contractors, should be regularly reviewed and audited. There should be a well-documented and understood process for emergency or hostile terminations, which may require manual intervention in the HR system and AD.
Evaluate GPOs
GPOs in AD are used to enforce policies on users and computers. GPOs should be regularly reviewed to ensure they continue to enforce the policies your organization adheres to.
Permissions Cleanup and Privileged Access Management
Permissions and administrative roles should also be regularly reviewed. Privileged groups and permissions should be designed and managed with the principle of least privilege in mind. You should refine permissions and ensure that access rights align with current roles and responsibilities. AD service accounts often fall through the cracks of reviews and audits because they are not tied to a particular individual. Make sure AD service accounts are audited as part of this process.
Metadata Cleanup
There are objects in AD besides users and computers that can easily be overlooked. For example, sites and subnets are often neglected. DNS zones and out-of-date records can add to clutter in a directory.
Most AD admins do not work with this metadata as frequently as they work with users and computers. Knowing and understanding how sites and subnets affect replication and authentication is important when it comes to updating or deleting them. Regular reviews of the network topology should be coordinated with the network team, so they can be reflected in AD sites and subnets. Clean up server metadata on a regular schedule to improve system performance, enhance the efficiency of replication, and reduce administrative overhead.
Maintain Entra ID in Tandem with AD
Most organizations today are using Entra ID (formerly Azure AD) in conjunction with on-premises AD. It is important to ensure that Entra ID and AD users are managed together. Typically, this is accomplished using Microsoft Entra Connect (formerly Azure AD Connect). If an AD user is created, it is also created in Entra ID. Conversely, if an account is deleted in AD, it is deleted in Entra ID. It is crucial to ensure that specific users in AD that are not required in Entra ID, such as privileged AD accounts and service accounts, are excluded from synchronization.
Best Practices for AD Cleanup
Once you are operating with a clean AD, it is important to ensure that it remains clean. Let’s look at a few AD maintenance best practices.
AD Maintenance Documentation
Maintaining documentation of what is done and how it is accomplished is critical, especially as the responsibility for identity management scales out to other teams. The amount of detail required in documentation will vary from organization to organization. Documentation should make it easy for someone to understand how and why a system works the way it does. Documentation with an extensive level of detail can be challenging to assimilate and can quickly become outdated. Documentation should be concise and easy to regularly update.
Routine Maintenance Schedule
Routine maintenance is crucial not only for ongoing AD health and security reasons but also for completing audits and ensuring compliance. Ravenswood Technology Group has published a detailed AD maintenance schedule with specific advice on when and how often to conduct essential maintenance tasks to keep your AD protected.
Deploy AD Changes in Pre-Production First
Before applying changes in any production AD environment, you should test them in a pre-production environment. Conducting full, end-to-end testing for AD changes can be difficult. While most organizations have a pre-production environment for AD, it is rare that it includes pre-production instances of all the systems and applications that depend on AD. A change in AD may seem simple, but it can be difficult to determine how that change could affect systems that are not in the test environment. One way to help mitigate that risk is to include a rollback plan in the change control process. The deployment of the change and rollback method should be tested.
Monitoring and Auditing AD
Continuous monitoring and auditing play an essential role in managing an AD environment. Review policies and processes on a regular basis and verify they are implemented properly. For example:
- Are terminated users disabled in AD the same day they were terminated in the HR system?
- Do you get an alert if a new GPO is linked to the root of the domain?
- Do you get an alert if a member is added to the Domain Admins group?
It is important to configure monitoring with a very high signal-to-noise ratio. If an alert fires, it should be actionable. If a team is receiving a hundred alerts per hour, day in and day out, those alerts are most likely ignored and provide no value.
Conclusion
Maintaining a clean AD environment is crucial to the overall security and efficiency of your IT infrastructure. Regular maintenance, testing, automation, and monitoring are essential for keeping AD protected. If you would like help with cleaning up your AD environment, contact the experts at Ravenswood Technology today.
