CVE-2020-16895
📋 TL;DR
This Windows vulnerability allows an authenticated attacker to delete arbitrary files by exploiting improper handling of process crashes in Windows Error Reporting Manager. Successful exploitation leads to local privilege escalation. All Windows systems with the vulnerable component are affected.
💻 Affected Systems
- Microsoft Windows
📦 What is this software?
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains SYSTEM privileges, deletes critical system files, and achieves complete system compromise or denial of service.
Likely Case
Local attacker escalates privileges to delete targeted files, potentially enabling further exploitation or data destruction.
If Mitigated
With proper access controls and patching, impact is limited to authenticated users with limited privileges.
🎯 Exploit Status
Requires authenticated access and specially crafted application. Proof-of-concept code has been published.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: October 2020 security updates (KB4579311, KB4577671, etc.)
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16895
Restart Required: Yes
Instructions:
1. Apply October 2020 Windows security updates via Windows Update. 2. For enterprise: Deploy through WSUS or SCCM. 3. Verify update installation with 'wmic qfe list' showing appropriate KB.
🔧 Temporary Workarounds
Disable Windows Error Reporting Service
windowsTemporarily disable the vulnerable service to prevent exploitation
sc config WerSvc start= disabled
sc stop WerSvc
🧯 If You Can't Patch
- Restrict user privileges using least privilege principle
- Implement application whitelisting to prevent execution of unauthorized applications
🔍 How to Verify
Check if Vulnerable:
Check if October 2020 security updates are NOT installed: wmic qfe list | findstr KB4579311 KB4577671Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify October 2020 security updates ARE installed: wmic qfe list | findstr KB4579311 KB4577671📡 Detection & Monitoring
Log Indicators:
- Event ID 1000 application crashes with WerFault.exe
- Unexpected file deletion events in security logs
- WerSvc service stopping/starting abnormally
Network Indicators:
- No network indicators - local exploitation only
SIEM Query:
EventID=1000 AND ProcessName="WerFault.exe" | stats count by Computer, User