CVE-2022-30220
📋 TL;DR
CVE-2022-30220 is an elevation of privilege vulnerability in the Windows Common Log File System (CLFS) driver. It allows authenticated attackers to gain SYSTEM-level privileges on affected Windows systems. This affects Windows 10, Windows 11, and Windows Server systems with the vulnerable driver.
💻 Affected Systems
- Windows 10
- Windows 11
- Windows Server 2019
- Windows Server 2022
📦 What is this software?
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 11 by Microsoft
Windows 11 by Microsoft
Windows 7 by Microsoft
Windows 7 by Microsoft
Windows 8.1 by Microsoft
Windows 8.1 by Microsoft
Windows Rt 8.1 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain full SYSTEM privileges, enabling complete system compromise, lateral movement, persistence establishment, and disabling of security controls.
Likely Case
Privileged attackers escalate from standard user to SYSTEM, bypassing security boundaries to install malware, steal credentials, or access sensitive data.
If Mitigated
With proper patch management and least privilege principles, impact is limited to isolated systems with no lateral movement capability.
🎯 Exploit Status
Exploitation requires local access and user privileges. Multiple proof-of-concepts exist in security research community.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: July 2022 security updates (KB5015807, KB5015814, etc.)
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-30220
Restart Required: Yes
Instructions:
1. Apply July 2022 Windows security updates via Windows Update. 2. For enterprise: Deploy through WSUS, SCCM, or Microsoft Update Catalog. 3. Restart systems after patch installation.
🔧 Temporary Workarounds
Restrict CLFS driver access
windowsApply security policies to restrict access to CLFS driver for non-administrative users
🧯 If You Can't Patch
- Implement strict least privilege principles to limit user account capabilities
- Deploy application control solutions to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check Windows version and compare with patched versions in Microsoft advisory. Vulnerable if prior to July 2022 updates.Check Version:
wmic os get caption, version, buildnumberVerify Fix Applied:
Verify Windows Update history shows July 2022 security updates installed and system version matches patched versions.📡 Detection & Monitoring
Log Indicators:
- Event ID 4688 with CLFS driver access from non-system accounts
- Unexpected privilege escalation events
- CLFS.sys driver manipulation attempts
Network Indicators:
- Lateral movement following local privilege escalation
SIEM Query:
EventID=4688 AND ProcessName LIKE '%clfs%' AND SubjectUserName NOT IN ('SYSTEM', 'LOCAL SERVICE', 'NETWORK SERVICE')