CVE-2019-9930
📋 TL;DR
CVE-2019-9930 is an integer overflow vulnerability affecting various Lexmark printers and multifunction devices. This vulnerability could allow remote attackers to execute arbitrary code or cause denial of service. Organizations using affected Lexmark devices are at risk.
💻 Affected Systems
- Various Lexmark printers and multifunction devices
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with SYSTEM/root privileges leading to complete device compromise, lateral movement into corporate networks, and persistent backdoor installation.
Likely Case
Denial of service causing printer/multifunction device crashes, rendering devices unusable until rebooted or repaired.
If Mitigated
Limited impact with proper network segmentation and access controls, potentially only causing temporary service disruption.
🎯 Exploit Status
Integer overflow vulnerabilities typically require specific knowledge of the affected code and memory layout to exploit reliably.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware updates available through Lexmark support
Vendor Advisory: http://support.lexmark.com/index?page=content&id=TE920&locale=EN&userlocale=EN_US
Restart Required: Yes
Instructions:
1. Visit Lexmark support site with TE920 advisory. 2. Identify your specific device model. 3. Download latest firmware update. 4. Apply firmware update following Lexmark instructions. 5. Reboot device after update completes.
🔧 Temporary Workarounds
Network Segmentation
allIsolate Lexmark devices to separate VLAN with restricted access
Disable Unnecessary Services
allTurn off unused network services and protocols on Lexmark devices
🧯 If You Can't Patch
- Implement strict network access controls allowing only authorized IP addresses to communicate with Lexmark devices
- Monitor network traffic to Lexmark devices for anomalous patterns and implement intrusion detection rules
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against Lexmark's patched versions list in advisory TE920Check Version:
Access Lexmark device web interface > Settings > Device Information > Firmware VersionVerify Fix Applied:
Confirm firmware version has been updated to latest available version from Lexmark📡 Detection & Monitoring
Log Indicators:
- Device crash/reboot logs
- Unusual network service access attempts
- Firmware modification attempts
Network Indicators:
- Unusual traffic patterns to printer ports
- Exploit-like payloads sent to Lexmark devices
- Unexpected outbound connections from printers
SIEM Query:
source="lexmark-printer" AND (event_type="crash" OR event_type="reboot" OR port_scan_detected=true)