In early 2025, security researchers discovered a vulnerability, now tracked as CVE-2025-27736, affecting the Windows Power Dependency Coordinator (WPDC). If you haven’t heard of WPDC, it’s a background service introduced in modern Windows releases to manage how power-dependent apps coordinate resource usage. It’s crucial for laptop battery life but, until recently, few suspected it could expose sensitive data.

The bug doesn’t allow hackers in from the internet or let malware take over your machine. However, it does let local attackers—anyone who can run code as a regular user on your PC—read information they should not see.

Why Does This Matter?

This vulnerability could let an attacker who has limited access (think: a low-level employee, malware running with basic privileges, or a guest user) uncover sensitive details—passwords, device identifiers, user activity, and more—by abusing WPDC’s overzealous logging and mishandling of files.

Depending on what personal or business data gets processed by your system, this kind of exposure could be a big deal.

Vulnerability Details

You can read the official notice here:
- CVE-2025-27736 on Microsoft Security Portal
- NVD entry

Technical summary:
When WPDC updates its log and coordination files in C:\ProgramData\Microsoft\WPDC\Logs, it fails to set proper file permissions. This makes them readable by any authenticated user—even though the contents might include:

Some Windows Server 2022 builds

Check Microsoft's advisory for the complete current list.

Proof-of-Concept Exploit (Local)

Let’s say you are an attacker with a user shell (e.g., PowerShell, CMD, or an app running as a standard user).

A quick script in PowerShell lists all available logs and prints out any lines mentioning “password”, “Auth”, or “Token”.

# PowerShell snippet: Search for sensitive patterns in WPDC logs
$logDir = "C:\ProgramData\Microsoft\WPDC\Logs"
Get-ChildItem $logDir -File | ForEach-Object {
    try {
        Get-Content $_.FullName -ErrorAction Stop | 
            Select-String -Pattern "password|Auth|Token|User|Session" -SimpleMatch |
            ForEach-Object { "$($_.Path): $($_.Line)" }
    } catch {}
}

What it does:

WPDC runs under a privileged system account.

2. It regularly dumps diagnostic information, including data about user sessions and app power requests, into log files.
3. Those log files, by default, are world-readable because the WPDC installer or updater set incorrect ACLs (“Everyone:Read”).

Usernames and process names (sometimes even window titles)

- Timestamps of user/application actions

A determined attacker could use this data to escalate privileges, impersonate users, or target other attacks.

Open a CMD or PowerShell window as a standard (non-admin) user and try reading WPDC logs

# Test read permissions as a standard user
Test-Path "C:\ProgramData\Microsoft\WPDC\Logs"
(Get-ChildItem "C:\ProgramData\Microsoft\WPDC\Logs" -File).Count
Get-Content "C:\ProgramData\Microsoft\WPDC\Logs\wpdc-2025-02-20.log" -TotalCount 10

If the final command prints out log lines, your system is likely exposed.

What Has Microsoft Done?

Microsoft released security updates in March 2025. These updates fix file permissions on both new and existing WPDC log files, ensuring only administrators and SYSTEM can read them. Read more here:
- Microsoft Patch Tuesday March 2025

If you can't patch right now, manually tighten permissions on the log folder

icacls "C:\ProgramData\Microsoft\WPDC\Logs" /inheritance:r /grant:r "Administrators:F" "SYSTEM:F" /remove "Users" "Everyone"

> Warning: Modifying permissions on system folders can cause issues if done incorrectly. Always create a backup.

References

- CVE-2025-27736 @ Microsoft
- NVD: CVE-2025-27736
- MSRC Security Advisory

Final Thoughts

CVE-2025-27736 is a reminder that local privilege boundaries matter, even if an attacker “only” has user access. Always keep your systems updated, watch for odd logging practices by quiet background services, and restrict file permissions on folders holding sensitive logs.

If this helped you, share it with your tech team or friends who manage Windows machines. The more people patch, the more secure we all are!

Timeline

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