CVE-2018-15520
📋 TL;DR
This vulnerability is a buffer overflow in various Lexmark printer and multifunction devices that could allow remote code execution. Attackers could exploit this to take control of affected devices, potentially accessing network resources or sensitive data. Organizations using vulnerable Lexmark devices are affected.
💻 Affected Systems
- Various Lexmark printer and multifunction devices
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote attacker gains full control of device, pivots to internal network, exfiltrates sensitive data, or deploys ransomware.
Likely Case
Device compromise leading to denial of service, unauthorized access to printed documents, or use as network foothold.
If Mitigated
Isolated device with proper network segmentation prevents lateral movement; impact limited to device functionality.
🎯 Exploit Status
CVSS 9.8 suggests low attack complexity and no authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory TE892 for specific firmware versions
Vendor Advisory: http://support.lexmark.com/index?page=content&id=TE892
Restart Required: Yes
Instructions:
1. Access Lexmark support site 2. Search for advisory TE892 3. Identify affected device models 4. Download latest firmware 5. Apply firmware update via device web interface or management tools 6. Reboot device
🔧 Temporary Workarounds
Network Segmentation
allIsolate Lexmark devices on separate VLAN with restricted access
Disable Unnecessary Services
allTurn off unused network services on printer interfaces
🧯 If You Can't Patch
- Implement strict network access controls to limit device communication
- Monitor device logs for unusual activity and network traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against vendor advisory TE892 listCheck Version:
Access device web interface > Settings > Device Information > Firmware VersionVerify Fix Applied:
Confirm firmware version matches patched version in advisory📡 Detection & Monitoring
Log Indicators:
- Unusual network connections to printer ports
- Firmware modification attempts
- Buffer overflow error messages in device logs
Network Indicators:
- Unexpected traffic to printer management ports (typically 80, 443, 9100)
- Exploit pattern traffic
SIEM Query:
source_ip=printer_ip AND (port=80 OR port=443 OR port=9100) AND bytes_sent>threshold