Microsoft Defender for Identity Recommended Actions: Change password of built-in domain Administrator account

Identity leverages Secure Score with twenty-seven recommended actions. In a series of blog posts, I will go through all twenty-seven recommended actions and what they mean, a plan of approach, their impact, and my security recommendations, hopefully helping others. The twenty-sixth  one in the series is the “Change password of built-in domain Administrator account” recommended action.

Introduction

You have twenty-seven recommendations if you filter the Secure Score recommended actions for Microsoft Defender for Identity.

• Resolve unsecure domain configurations
• Resolve unsecure account attributes
• Remove dormant accounts from sensitive groups
• Protect and manage local admin passwords with Microsoft LAPS
• Configure VPN integration
• Reduce lateral movement path risk to sensitive entities
• Stop clear text credentials exposure
• Disable Print spooler service on domain controllers
• Stop weak cipher usage
• Remove unsecure SID history attributes from entities
• Modify unsecure Kerberos delegations to prevent impersonation
• Install Defender for Identity Sensor on all Domain Controllers
• Set a honeytoken account
• Start your Defender for Identity deployment, installing Sensors on DC’s and other eligible servers
• Accounts with non-default Primary Group ID
• Change Domain Controller computer account old password
• Reversible passwords found in GPOs
• Unsafe permissions on the DnsAdmins group
• GPO assigns unprivileged identities to local groups with elevated privileges
• Remove access rights on suspicious accounts with the Admin SDHolder permission
• Remove local admins on identity assets
• Remove non-admin accounts with DCSync permissions
• GPO can be modified by unprivileged accounts
• Built-in Active Directory Guest account is enabled
• Change password for krbtgt account
• Change password of built-in domain Administrator account
• Ensure that all privileged accounts have the configuration flag

Some recommended actions are easy to configure, but others require time, proper planning, auditing, and expertise. This blog post will review the recommended action of “Change password of built-in domain Administrator account.”

Update: Microsoft keeps updating the recommended actions list. I will do my best to keep the list up-to-date.

Change password of built-in domain Administrator account

The built-in domain Administrator account represents one of the most powerful and critical accounts in any Active Directory environment. Created automatically during domain installation, this default account possesses unrestricted access to every resource within the domain and holds full control over all domain management functions. Unlike other privileged accounts that can be created and deleted as needed, the built-in Administrator account is a permanent fixture in your Active Directory infrastructure that cannot be removed, making its security posture a fundamental concern for domain protection.

Understanding the unique characteristics of the built-in Administrator account is essential for maintaining a secure Active Directory environment. This account differs from other administrative accounts in several important ways. It carries the well-known Security Identifier (SID) ending in 500, making it easily identifiable to both legitimate administrators and potential attackers. The account maintains its privileged status regardless of group membership changes, and it cannot be locked out through failed login attempts, which is a feature designed to prevent accidental lockouts but also creates unique security considerations.

The security implications of the built-in Administrator account are significant precisely because of its elevated privileges and predictable nature. Attackers specifically target this account knowing that successful compromise grants them complete control over the domain and all its resources. The account’s inability to be deleted means that organizations cannot simply remove this potential attack vector, and its well-known SID makes it a consistent target across all Active Directory environments. These factors combine to make the built-in Administrator account one of the most attractive targets for attackers attempting to gain domain-wide access.

The Risk of Neglecting Built-in Administrator Password Rotation

What makes this account particularly vulnerable in many organizations is a common operational pattern where it is rarely used in day-to-day administration. Many organizations establish the built-in Administrator account password during initial domain setup and then create separate named administrator accounts for routine administrative tasks. While this practice of using named accounts is excellent for accountability and auditing purposes, it often leads to the built-in Administrator password remaining unchanged for extended periods, sometimes years. This creates a scenario where a highly privileged account with predictable credentials sits dormant in the environment, representing a significant security risk that is easily overlooked in routine security reviews.

Mitigating the Risk Through Regular Password Management

Protecting your Active Directory environment from attacks targeting the built-in domain Administrator account requires a disciplined approach to password management. Microsoft recommends that the built-in Administrator account password should be reset at least every 180 days to reduce the window of opportunity for attackers and minimize the risk of credential compromise. Organizations with heightened security requirements or those operating in high-risk environments should consider implementing even more frequent password rotations to further limit exposure.

The process of resetting the built-in Administrator account password is straightforward and can be accomplished through several methods. The most common approach is using Active Directory Users and Computers, where administrators can navigate to the Users container within the domain, locate the Administrator account, right-click and select Reset Password, then enter and confirm the new password. This simple procedure takes only minutes to complete but provides substantial security benefits by invalidating any previously compromised credentials and resetting the exposure timeline.

Unlike the KRBTGT account which requires a complex dual-reset procedure with waiting periods, the built-in Administrator account password can be changed in a single operation without concern for authentication disruptions. There is no need to wait between password changes or worry about replication timing, as the new password takes effect immediately across your domain controllers through normal Active Directory replication. This simplicity makes it even more important to establish and maintain a regular rotation schedule, as there are no technical barriers or operational complexities to prevent timely password updates.

When implementing your password rotation strategy, it is essential to consider how the new password will be securely stored and accessed. Many organizations use enterprise password management solutions or privileged access management systems to store the built-in Administrator password in an encrypted vault with strict access controls and comprehensive audit logging. This approach ensures that the password is available when needed for emergency recovery scenarios while maintaining tight security around who can access it and creating a clear audit trail of all password retrievals.

The password rotation process should be incorporated into your organization’s standard security maintenance procedures and documented in your change management system. Establish a clear schedule for rotation, assign responsibility for executing the password change to specific team members, and implement monitoring or alerting mechanisms to ensure the rotation occurs on schedule. When Microsoft Defender for Identity flags the built-in Administrator account password as exceeding 180 days, treat this as a priority remediation task rather than a routine suggestion. The effort required to reset the password is minimal, especially when compared to the potential impact of a compromised account with unrestricted domain access.

It is equally important to consider the broader security context around the built-in Administrator account beyond just password rotation. Ensure that the account is not being used for routine administrative tasks, as this increases the risk of credential exposure through everyday operations. Monitor the account for any unexpected authentication attempts or successful logins, as the built-in Administrator should typically remain dormant except for specific emergency recovery scenarios or planned maintenance activities.

For organizations discovering that their built-in Administrator password has not been changed in significantly longer than 180 days, immediate action is warranted. Prioritize this password reset as part of your security hardening efforts, and use the opportunity to establish formal procedures that will prevent this situation from recurring. Document the new password according to your organization’s secure storage procedures, communicate the change to relevant stakeholders who may need emergency access, and set calendar reminders or automated alerts to ensure future rotations occur within the recommended timeframe. By maintaining this discipline around built-in Administrator password management, you significantly reduce one of the most common and easily exploitable vulnerabilities in Active Directory environments.

Conclusion

The built-in domain Administrator account’s unrestricted privileges and permanent presence in your Active Directory environment make it a prime target for attackers. Microsoft Defender for Identity’s recommendation to reset this password every 180 days is a straightforward security control that directly reduces your organization’s exposure to credential-based attacks. Unlike the complex procedures required for KRBTGT password rotation, changing the built-in Administrator password is a simple operation that can be completed in minutes without risk of service disruption.

If your Defender for Identity assessment reveals that your built-in Administrator password has not been changed in over 180 days, treat this as an immediate priority. The minimal effort required to reset this password stands in stark contrast to the catastrophic impact of a compromised account with complete domain control. Establish a regular rotation schedule, implement secure password storage procedures, and ensure this critical security practice becomes part of your routine maintenance calendar. By maintaining discipline around built-in Administrator password management, you are closing one of the most commonly exploited vulnerabilities in Active Directory environments.