CVE-2023-24929
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on systems using vulnerable Microsoft PostScript and PCL6 Class Printer Drivers. Attackers can exploit this by sending specially crafted print jobs to affected systems. Organizations using Windows print servers or workstations with these drivers are affected.
💻 Affected Systems
- Microsoft PostScript Printer Driver
- Microsoft PCL6 Class Printer Driver
📦 What is this software?
Windows 10 1507 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 20h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 11 21h2 by Microsoft
Windows 11 22h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining SYSTEM privileges, enabling lateral movement, data exfiltration, and persistent access to the network.
Likely Case
Privilege escalation leading to installation of malware, ransomware deployment, or credential theft from compromised systems.
If Mitigated
Limited impact with proper network segmentation, print server isolation, and least privilege configurations preventing lateral movement.
🎯 Exploit Status
Exploitation requires ability to send print jobs to vulnerable systems. No public exploit code available at time of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: May 2023 security updates (specific KB numbers vary by Windows version)
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-24929
Restart Required: Yes
Instructions:
1. Apply May 2023 Windows security updates from Windows Update. 2. For enterprise environments, deploy patches via WSUS, SCCM, or Intune. 3. Restart affected systems after patch installation.
🔧 Temporary Workarounds
Disable vulnerable printer drivers
windowsRemove or disable Microsoft PostScript and PCL6 Class Printer Drivers from systems
Remove-PrinterDriver -Name "Microsoft PostScript Printer Driver"
Remove-PrinterDriver -Name "Microsoft PCL6 Class Printer Driver"
Restrict print spooler access
windowsConfigure firewall rules to restrict access to print spooler service (port 445, 139, 9100)
New-NetFirewallRule -DisplayName "Block Print Spooler" -Direction Inbound -Protocol TCP -LocalPort 445,139,9100 -Action Block
🧯 If You Can't Patch
- Isolate print servers in separate network segments with strict firewall rules
- Implement network-based intrusion detection for anomalous print job traffic
🔍 How to Verify
Check if Vulnerable:
Check installed printer drivers: Get-PrinterDriver | Select Name, Manufacturer, DriverVersionCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify May 2023 security updates are installed: Get-HotFix | Where-Object {$_.InstalledOn -like "*05/2023*"}📡 Detection & Monitoring
Log Indicators:
- Windows Event ID 307 from PrintService
- Unusual print job submissions in PrintService logs
- Failed print driver loading events
Network Indicators:
- Anomalous SMB traffic to print servers
- Unexpected print job submissions from unusual sources
- Port 9100 traffic from unauthorized hosts
SIEM Query:
source="Windows" AND (event_id=307 OR "PrintService") AND ("PostScript" OR "PCL6")