CVE-2023-24909
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected systems by exploiting integer overflow in Microsoft PostScript and PCL6 Class Printer Drivers. It affects Windows systems with vulnerable printer drivers installed, primarily impacting print servers and workstations with shared printers.
💻 Affected Systems
- Microsoft Windows PostScript Printer Driver
- Microsoft Windows PCL6 Printer Driver
📦 What is this software?
Windows 10 1607 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 SYSTEM privileges, enabling lateral movement, data exfiltration, and persistent backdoor installation across the network.
Likely Case
Privilege escalation leading to unauthorized access to sensitive documents, installation of malware, or disruption of printing services.
If Mitigated
Limited impact with proper network segmentation and restricted printer driver permissions, potentially causing service disruption but preventing full compromise.
🎯 Exploit Status
Exploitation requires sending specially crafted print jobs to vulnerable systems, potentially via SMB or other printing protocols.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: May 2023 security updates (KB5026372 for Windows 10, KB5026371 for Windows 11, etc.)
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-24909
Restart Required: Yes
Instructions:
1. Apply May 2023 Windows security updates via Windows Update. 2. For enterprise environments, deploy updates through WSUS or SCCM. 3. Restart affected systems after patch installation.
🔧 Temporary Workarounds
Disable vulnerable printer drivers
windowsRemove or disable PostScript and PCL6 Class Printer Drivers if not required
Remove-PrinterDriver -Name "PostScript Printer Driver"
Remove-PrinterDriver -Name "PCL6 Printer Driver"
Restrict printer sharing
windowsDisable network printer sharing to prevent remote exploitation
Set-NetFirewallRule -DisplayGroup "File and Printer Sharing" -Enabled False
🧯 If You Can't Patch
- Segment print servers from critical networks using firewalls
- Implement strict access controls to limit who can send print jobs to vulnerable systems
🔍 How to Verify
Check if Vulnerable:
Check installed printer drivers via PowerShell: Get-PrinterDriver | Select Name, Manufacturer, DriverVersionCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify Windows Update history contains May 2023 security updates and check printer driver versions are updated📡 Detection & Monitoring
Log Indicators:
- Unusual print job failures in Print Service logs
- Multiple failed printer driver installation attempts
- Suspicious network printing activity
Network Indicators:
- Unusual SMB traffic to print spooler ports (TCP 139, 445)
- Large or malformed print jobs from unexpected sources
SIEM Query:
source="Windows Security" EventID=4625 AND ProcessName="spoolsv.exe" OR source="Print Service" EventID=10