CVE-2023-24876
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected systems by exploiting a heap-based buffer overflow in Microsoft PostScript and PCL6 Class Printer Drivers. Attackers can achieve this by sending specially crafted print jobs to vulnerable systems. Organizations using affected Windows versions with these printer drivers are at risk.
💻 Affected Systems
- Microsoft Windows PostScript Printer Driver
- Microsoft Windows PCL6 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 SYSTEM privileges, enabling data theft, ransomware deployment, lateral movement, and persistent backdoor installation.
Likely Case
Privilege escalation leading to administrative control over affected systems, enabling further network exploitation and data exfiltration.
If Mitigated
Limited impact with proper network segmentation, print server isolation, and restricted printer driver permissions preventing successful exploitation.
🎯 Exploit Status
Exploitation requires sending malicious print jobs to vulnerable systems. Attackers need network access to print services and may require authentication depending on configuration.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: March 2023 security updates
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-24876
Restart Required: Yes
Instructions:
1. Apply March 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 affected PostScript and PCL6 printer drivers from systems
Remove-PrinterDriver -Name "Microsoft PostScript Printer Driver"
Remove-PrinterDriver -Name "Microsoft PCL6 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
- Network segment print servers and restrict access to authorized users only
- Disable printer sharing and remove unnecessary printer drivers from workstations
🔍 How to Verify
Check if Vulnerable:
Check installed printer drivers: Get-PrinterDriver | Select Name, DriverVersionCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify March 2023 updates installed: Get-HotFix | Where-Object {$_.InstalledOn -like "*03/2023*"}📡 Detection & Monitoring
Log Indicators:
- Windows Event ID 307 (Print Spooler errors)
- Unusual print job submissions from unexpected sources
- Spoolsv.exe crashes or abnormal behavior
Network Indicators:
- Unusual SMB traffic to print servers
- Multiple failed print job submissions
- Traffic to print spooler ports from unauthorized sources
SIEM Query:
source="WinEventLog:Security" EventID=307 | stats count by src_ip, dest_ip