CVE-2023-29343
📋 TL;DR
This vulnerability in Sysinternals Sysmon for Windows allows attackers to elevate privileges from a low-privileged user to SYSTEM level. It affects Windows systems running vulnerable versions of Sysmon. Attackers must already have local access to exploit this vulnerability.
💻 Affected Systems
- Sysinternals Sysmon
📦 What is this software?
Windows Sysmon by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full SYSTEM compromise allowing complete control over the affected system, installation of persistent malware, credential theft, and lateral movement across the network.
Likely Case
Privilege escalation from standard user to SYSTEM, enabling installation of additional malware, disabling security controls, and accessing sensitive system resources.
If Mitigated
Limited impact if proper endpoint protection, least privilege principles, and network segmentation are in place to contain lateral movement.
🎯 Exploit Status
Exploitation requires local access and low-privileged user credentials. The vulnerability is in improper link resolution allowing privilege escalation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Sysmon version 14.16 or later
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-29343
Restart Required: No
Instructions:
1. Download latest Sysmon from Microsoft Sysinternals website. 2. Stop Sysmon service: 'sc stop Sysmon'. 3. Update Sysmon: 'Sysmon.exe -u'. 4. Start Sysmon service: 'sc start Sysmon'.
🔧 Temporary Workarounds
Remove vulnerable Sysmon
windowsUninstall Sysmon if not required for monitoring
Sysmon.exe -u force
Restrict Sysmon directory permissions
windowsSet strict ACLs on Sysmon installation directory to prevent unauthorized access
icacls "C:\Sysmon" /inheritance:r /grant:r "SYSTEM:(OI)(CI)F" "Administrators:(OI)(CI)F" /deny "Users:(OI)(CI)(DE,DC)"
🧯 If You Can't Patch
- Implement strict least privilege principles - ensure users don't have unnecessary local admin rights
- Monitor for suspicious process creation and privilege escalation attempts using EDR/SIEM tools
🔍 How to Verify
Check if Vulnerable:
Check Sysmon version with: 'Sysmon.exe -s' or 'sc query Sysmon' and look for version numberCheck Version:
Sysmon.exe -sVerify Fix Applied:
Verify Sysmon version is 14.16 or later using: 'Sysmon.exe -s'📡 Detection & Monitoring
Log Indicators:
- Sysmon Event ID 1 (Process creation) showing unexpected parent-child relationships
- Sysmon Event ID 10 (Process access) showing privilege escalation patterns
- Windows Security Event 4688 showing process creation with elevated privileges
Network Indicators:
- Unusual outbound connections from SYSTEM processes
- Lateral movement attempts from compromised systems
SIEM Query:
source="Sysmon" EventID=1 OR EventID=10 | where ParentImage contains "Sysmon" OR TargetImage contains "Sysmon" | stats count by Image, ParentImage, CommandLine