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How the CVE Works:
CVE-2025-26633 is an improper neutralization vulnerability in Microsoft Management Console (MMC) that allows local attackers to bypass security features. The flaw arises due to insufficient sanitization of user-supplied input in MMC snap-ins, enabling malicious actors to inject crafted data and circumvent access controls. Attackers can exploit this by manipulating registry keys or configuration files loaded by MMC, leading to privilege escalation or unauthorized administrative actions. The vulnerability leverages improper handling of dynamic link library (DLL) loading paths, allowing arbitrary code execution in the context of the MMC process.
DailyCVE Form:
Platform: Windows
Version: MMC 5.0+
Vulnerability: Security Bypass
Severity: Critical
Date: 04/17/2025
What Undercode Say:
Exploitation:
- Registry Manipulation: Modify `HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MMC` to load a malicious DLL.
- DLL Hijacking: Place a rogue DLL in a writable directory referenced by MMC’s search path.
- Code Execution: Craft a malicious snap-in (.msc file) to trigger the payload.
Protection:
1. Apply Microsoft’s patch KB5025299 or later.
2. Restrict MMC execution via Group Policy:
Set-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" -Name "EnableMMC" -Value 0
3. Enable Attack Surface Reduction (ASR) rules:
Add-MpPreference -AttackSurfaceReductionRules_Ids "56a863a9-875e-4185-98a7-b882c64b5ce5" -AttackSurfaceReductionRules_Actions Enabled
Detection:
- Monitor MMC process creation for unusual child processes:
Get-WinEvent -LogName "Microsoft-Windows-Sysmon/Operational" | Where-Object { $<em>.Id -eq 1 -and $</em>.ParentProcessName -eq "mmc.exe" } - Audit registry changes under
HKLM\SOFTWARE\Microsoft\MMC\SnapIns.
Mitigation Script:
Block untrusted MMC snap-ins
if (Test-Path "$env:ProgramData\Microsoft\MMC.msc") {
Remove-Item -Force "$env:ProgramData\Microsoft\MMC.msc"
}
References:
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
