Discover the latest Active Directory vulnerability, CVE-2025-29810, and learn how to safeguard your business from potential risks.
In April 2025, Microsoft publicly disclosed CVE-2025-29810, a high-severity privilege escalation vulnerability affecting Active Directory Domain Services (AD DS), a core component of Windows Server environments.
At the heart of this vulnerability lies a flaw in access control logic—the very mechanism that decides who can access what across your IT environment. Specifically, authenticated users (i.e., users with valid credentials on the domain) can exploit this weakness to elevate their permissions, gaining access to resources and administrative capabilities they shouldn’t have.
Active Directory (AD) acts as the central gatekeeper of user accounts, computers, and security policies across a Windows-based network. It controls:
- Logins and authentication
- User and group permissions
- Access to files, applications, and services
- Policy enforcement and auditing
When AD is compromised, the attacker isn’t just accessing a file or application—they’re gaining control of the entire digital identity layer of your organization.
While Microsoft has not disclosed full exploitation details (to limit abuse), what we know is:
The vulnerability stems from improper enforcement of access control rules in Active Directory Domain Services.
An attacker must be authenticated (e.g., a regular domain user or compromised account).
With this foothold, they can perform actions that are typically restricted to privileged users, such as:
- Modifying sensitive objects
- Escalating to domain administrator roles
- Bypassing role-based security restrictions
This means that even a low-privileged internal account could potentially be used to gain full control of the domain—a nightmare scenario for any organization.
While CVE-2025-29810 is technical in nature, the implications for your business go far beyond IT. A privilege escalation vulnerability in Active Directory doesn’t just threaten your servers — it threatens your organization’s ability to function, comply, and compete.
Active Directory is the backbone of your organization’s identity infrastructure. If compromised, it can disrupt everything from employee logins and application access to business workflows and communications. This level of disruption can:
- Delay internal operations and decision-making.
- Halt customer-facing services that rely on user authentication.
- Interfere with cloud-connected services that depend on hybrid identity models (e.g., Microsoft 365, Azure AD Connect).
In essence, the vulnerability puts your entire digital strategy at risk.
Responding to a breach caused by privilege escalation can quickly become expensive. Potential costs include:
Incident response and forensics to investigate the breach.
Downtime costs, including lost productivity and service availability.
Legal fees if sensitive data was accessed or leaked.
Customer churn due to lost trust.
Increased insurance premiums or denial of claims if negligence is found.
According to industry data, the average cost of a data breach involving identity compromise can exceed $4 million — and privilege escalation is often at the core of such incidents.
Microsoft Description:
"An improper access control vulnerability exists in Active Directory Domain Services. An attacker who successfully exploited this vulnerability could gain elevated privileges over the network. To exploit this vulnerability, an attacker must already have access and the ability to run code within the target network."
This tells us several key technical factors:
This vulnerability resides in Active Directory’s permission validation layer — likely involving security descriptor enforcement (DACL/SACL) on sensitive directory objects.
Access control in AD is governed by NT Security Descriptors, which define:
- Who can read, write, or modify an object
- What operations are allowed (create/delete/modify permissions, reset passwords, replicate objects, etc.)
Improper validation in this context likely means that certain security-sensitive operations (e.g., privilege assignments, replication rights, object manipulation) are not properly checking effective permissions — allowing lower-privileged users to execute tasks they should not be able to.
Based on Microsoft’s classification and historical context, here are likely technical areas where this issue may manifest:
- AD objects (user accounts, groups, containers) have DACLs that define who can modify them.
- A miscalculation in how permissions are resolved (e.g., inherited permissions not applied correctly) could let a low-privileged user modify a high-value object like:
- A domain admin account
- The AdminSDHolder container (which defines protected ACLs)
- A Group Policy Object (GPO) applied to privileged systems
- If a user can set the servicePrincipalName, scriptPath, memberOf, or similar attributes, they can trigger Kerberos delegation, abuse logon scripts, or inject backdoors via trusted services.
- Modifying the userAccountControl attribute could let an attacker elevate an account to Trusted for Delegation or enable disabled accounts.
- Misconfigured replication rights (Replicating Directory Changes + Replicating Directory Changes All) could be exposed due to faulty ACL inheritance.
- Attackers could simulate a Domain Controller using Mimikatz or DSInternals and pull password hashes for any account, including krbtgt, Administrator, and service accounts.
Regular penetration testing is vital in identifying internal threats and misconfigurations. Skilled cybersecurity professionals are essential to securing Active Directory environments against vulnerabilities like CVE-2025-29810.
A comprehensive security testing approach, including secure design, logging, and privilege separation, can significantly reduce your attack surface and enhance your overall security posture.
To mitigate the risks associated with CVE-2025-29810, apply Microsoft's patch immediately. Regularly audit directory permissions, enforce role-based access control, and implement the principle of least privilege.
Using tools like Microsoft Defender for Identity can aid in threat detection. Additionally, adopting Zero Trust principles can limit exposure from compromised accounts and enhance your security framework.
For more detailed information on CVE-2025-29810, refer to Microsoft’s official CVE page: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-29810.
Additionally, review Microsoft AD Security Best Practices and CISA Vulnerability Summaries for further guidance on securing your Active Directory environment.