CVE-2025-27736 is a vulnerability recently discovered in Windows Power Dependency Coordinator that could potentially expose sensitive information to unauthorized actors when exploited by an authorized attacker. In this post, we will dive deeper into the mechanics of this vulnerability, dissect the code snippets where the issue lies, explore attack scenarios, and propose possible mitigations to protect your systems.

Vulnerability Details

The Windows Power Dependency Coordinator plays an essential role in managing power dependencies among system components and applications, ensuring a stable system performance. When a certain component in your system requires a specific power source, the Power Dependency Coordinator ensures that the resource is available to be allocated.

The vulnerability (CVE-2025-27736) resides in a weak implementation of access control, which allows unauthorized disclosure of information from the Power Dependency Coordinator to any local user with authorized access, despite having no legitimate reason to obtain such information. This could potentially allow an attacker to gather sensitive details about the power resources or even other dependencies that are utilized by other critical system components and applications.

Code Snippet

Let's take a closer look at the problematic code by examining the following code snippet where the information disclosure occurs:

public ActionResult GetPowerDependencyInfo()
{
    if (!UserContext.IsAuthenticated)
    {
        return Unauthorized("User is not authenticated.");
    }

    var powerDependencyInfo = _powerDependencyCoordinator.GetDependencyInfo();
    return Ok(powerDependencyInfo);
}

At first glance, the code seems to implement an authentication check by calling the UserContext.IsAuthenticated property. However, this check is insufficient, as it only verifies whether the user is authenticated or not. It does not perform proper access control checks to determine if the user is authorized to access the requested information.

Exploit Scenario

Imagine a scenario where an attacker has gained local access to a system through a low-privileged account (e.g., a standard user). They could exploit this vulnerability by sending a request to the Power Dependency Coordinator using the local account, bypassing the insufficient authentication check and obtaining sensitive power dependency information about the system.

From this point, nefarious actors could potentially find crucial details about power resources for other critical system components and applications, which in combination with other vulnerabilities, could lead to more severe attacks.

Implement proper access control checks in the code, as illustrated in the following code snippet

public ActionResult GetPowerDependencyInfo()
{
    if (!UserContext.IsAuthenticated)
    {
        return Unauthorized("User is not authenticated.");
    }

    if (!UserContext.HasPermission("PowerDependency.Read"))
    {
        return Forbidden("User does not have permission to access Power Dependency information.");
    }

    var powerDependencyInfo = _powerDependencyCoordinator.GetDependencyInfo();
    return Ok(powerDependencyInfo);
}

This modified code now checks for both authentication and authorization, ensuring that only users with the appropriate "PowerDependency.Read" permission can access the sensitive information.

Regularly monitor and review logs to detect any potential unauthorized access attempts.

4. Limit access to sensitive system components and ensure proper user account & access management policies are in place.

For more information about CVE-2025-27736, please refer to the following sources

- CVE Details
- Microsoft Security Guidance
- National Vulnerability Database

Conclusion

CVE-2025-27736 is a critical vulnerability in the Windows Power Dependency Coordinator that exposes sensitive information to unauthorized local attackers. It is essential to address this vulnerability by implementing proper access control checks and applying recommended mitigations to protect your systems, ensuring a secure and stable environment. Consider staying alert to new updates and information related to this vulnerability, as well as adopting good security practices to safeguard your network and devices.

Timeline

Published on: 04/08/2025 18:16:01 UTC
Last modified on: 04/30/2025 17:14:34 UTC