CVE-2018-14839
📋 TL;DR
CVE-2018-14839 is an unauthenticated remote command execution vulnerability in LG N1A1 NAS devices. Attackers can execute arbitrary commands via HTTP POST requests, potentially gaining full control of affected systems. This affects LG N1A1 NAS devices running vulnerable firmware versions.
💻 Affected Systems
- LG N1A1 Network Attached Storage
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to install malware, steal data, pivot to internal networks, or use the device for botnet activities.
Likely Case
Remote code execution leading to data theft, ransomware deployment, or device takeover for malicious purposes.
If Mitigated
Limited impact if device is isolated from internet and internal networks with strict access controls.
🎯 Exploit Status
Exploit code is publicly available and requires minimal technical skill to execute.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware version after 3718.510 (check LG support for latest)
Vendor Advisory: https://www.lg.com/global/support/security-notice
Restart Required: Yes
Instructions:
1. Backup all data. 2. Download latest firmware from LG support site. 3. Log into NAS web interface. 4. Navigate to firmware update section. 5. Upload and apply new firmware. 6. Reboot device.
🔧 Temporary Workarounds
Network Isolation
allRemove device from internet exposure and restrict network access
Firewall Rules
linuxBlock HTTP/HTTPS access to NAS from untrusted networks
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Immediately disconnect device from internet and place behind strict firewall
- Implement network segmentation to isolate NAS from critical systems
🔍 How to Verify
Check if Vulnerable:
Check firmware version in web interface or via SSH: cat /etc/versionCheck Version:
ssh admin@nas-ip 'cat /etc/version' or check web interface System InformationVerify Fix Applied:
Verify firmware version is newer than 3718.510 and test HTTP POST requests to vulnerable endpoints return errors📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to NAS web interface
- Command execution patterns in system logs
- Unexpected process creation
Network Indicators:
- HTTP POST requests with command injection patterns to NAS port 80/443
- Outbound connections from NAS to suspicious IPs
SIEM Query:
source="nas-logs" AND (http_method="POST" AND (uri="*cgi*" OR uri="*command*" OR uri="*exec*"))🔗 References
- https://medium.com/%400x616163/lg-n1a1-unauthenticated-remote-command-injection-cve-2018-14839-9d2cf760e247
- https://medium.com/%400x616163/lg-n1a1-unauthenticated-remote-command-injection-cve-2018-14839-9d2cf760e247
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-14839
