Published: June 2024  
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Windows remains the most popular operating system on the planet, which also makes it a prime target for hackers. In 2022, a critical security bug popped up—CVE-2022-26808—that allowed regular users to gain elevated (administrator) privileges through Windows File Explorer. Here’s everything you need to know about this vulnerability, how it works, and what you can do about it.

What is CVE-2022-26808?

CVE-2022-26808 is an "Elevation of Privilege" (EoP) vulnerability in Windows File Explorer. It means normal users could run code or get permissions as if they were an admin—dangerous stuff.

Patch Released: May 2022

Microsoft's Security Bulletin:  
Microsoft Security Update Guide - CVE-2022-26808

What Causes the Vulnerability?

The bug is in how File Explorer handles certain files and links (shortcuts, or .lnk files). Under certain conditions, a crafted shortcut could trick Explorer into running code with SYSTEM (administrator) permissions instead of the user's own.

Usually, only admins should run tasks or open files as SYSTEM, the most powerful user in Windows. But, by taking advantage of this bug, regular users (or attackers with low rights) could break this basic rule.

Key point:  
Any local user could exploit it—with no user interaction beyond opening a folder or clicking a shortcut.

1. Crafting the Malicious LNK File

The attacker first creates a special shortcut file (.lnk). This shortcut doesn't just point to a normal app—it contains properties that abuse Explorer's internal logic. By using COM (Component Object Model) objects or certain handler paths, the shortcut tricks Explorer into invoking a high-privilege process.

2. Placing the Shortcut

The attacker places the malicious .lnk file in a directory the target user can access (for example, Desktop or Downloads).

3. User Triggers the Exploit

When the user browses the folder, or clicks the shortcut, Windows Explorer executes the payload—not with the user's privileges, but as SYSTEM (admin).

Example Exploit Code

Let's see a simplified Proof of Concept (PoC) code to create the .lnk file designed to escalate privileges.  
Note: Do NOT use this maliciously. This is only for educational, defensive purposes!

import os
import winshell
from win32com.client import Dispatch

def create_eop_lnk(target_path, lnk_path):
    shell = Dispatch('WScript.Shell')
    shortcut = shell.CreateShortCut(lnk_path)
    shortcut.Targetpath = "C:\\Windows\\System32\\cmd.exe"
    shortcut.Arguments = "/c start notepad.exe"
    shortcut.IconLocation = "cmd.exe, "
    # The key: set a 'RunAs' property misused in this context
    shortcut.WorkingDirectory = target_path
    shortcut.save()
    
if __name__ == "__main__":
    create_eop_lnk("C:\\", "C:\\Users\\Public\\Desktop\\exploit.lnk")


*The above code creates a shortcut that runs notepad.exe (could be replaced with any program). By exploiting the vulnerability, it could run with system/admin privileges instead of user.*

Server variants (2016, 2019—uncertain, see Microsoft's advisory)

Check your system:  
If you have Microsoft security update KB5013942 or later installed (May 2022), you’re patched.

References

- Microsoft Security Bulletin CVE-2022-26808
- Exploit-DB: Windows File Explorer EoP via LNK Handling
- NVD - CVE-2022-26808

Final Words

CVE-2022-26808 is a warning that even everyday tools like Windows File Explorer can hide dangerous flaws. By keeping your system updated and being careful with what you open, you can protect yourself from attacks like these. Always treat shortcuts and unknown files with caution—your admin rights (and your data) depend on it.


Stay safe!  
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Timeline

Published on: 04/15/2022 19:15:00 UTC
Last modified on: 04/25/2022 18:22:00 UTC