CVE-2018-17431
📋 TL;DR
CVE-2018-17431 is a critical authentication bypass vulnerability in Comodo UTM Firewall's web console that allows remote attackers to execute arbitrary code without authentication via a crafted URL. This affects all Comodo UTM Firewall installations before version 2.7.0 that have the web console exposed.
💻 Affected Systems
- Comodo Unified Threat Management Firewall
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root-level access, allowing attackers to install malware, steal sensitive data, pivot to internal networks, and maintain persistent access.
Likely Case
Remote code execution leading to firewall rule manipulation, credential theft, network reconnaissance, and potential ransomware deployment.
If Mitigated
Limited impact if web console is not internet-facing and proper network segmentation is in place, though internal attackers could still exploit.
🎯 Exploit Status
Multiple public proof-of-concept exploits exist, including Python scripts that demonstrate remote code execution. The vulnerability is trivial to exploit with publicly available tools.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.7.0 and later
Vendor Advisory: https://help.comodo.com/topic-72-1-766-10935-.html
Restart Required: Yes
Instructions:
1. Log into Comodo UTM admin interface
2. Navigate to System → Updates
3. Check for and apply available updates
4. Ensure version is 2.7.0 or higher
5. Reboot the appliance after update
🔧 Temporary Workarounds
Disable Web Console Access
allTemporarily disable web console access until patching can be completed
# Via CLI: utm-cli config set webconsole.enabled false
# Via GUI: System → Administration → Web Console → Disable
Network Access Control
linuxRestrict access to web console ports using firewall rules
# Example iptables rule: iptables -A INPUT -p tcp --dport 443 -s trusted_ip -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Immediately restrict network access to the web console interface using firewall rules to only allow trusted administrative IPs
- Implement network segmentation to isolate the UTM appliance from critical internal networks and monitor for suspicious outbound connections
🔍 How to Verify
Check if Vulnerable:
Check current version via admin interface (System → About) or CLI command 'utm-cli version show'. If version is below 2.7.0, system is vulnerable.Check Version:
utm-cli version showVerify Fix Applied:
Confirm version is 2.7.0 or higher and test that authentication is required for all web console access attempts.📡 Detection & Monitoring
Log Indicators:
- Unauthenticated access to web console endpoints
- Suspicious POST/GET requests with command injection patterns
- Unusual process execution from web server context
Network Indicators:
- HTTP requests to web console with crafted parameters
- Outbound connections from UTM appliance to suspicious external IPs
- Unusual traffic patterns from UTM management interface
SIEM Query:
source="utm_logs" AND (url="*cmd=*" OR url="*exec*" OR url="*system*" OR status="401" OR status="403")🔗 References
- http://packetstormsecurity.com/files/159246/Comodo-Unified-Threat-Management-Web-Console-2.7.0-Remote-Code-Execution.html
- https://drive.google.com/file/d/0BzFJhNQNHcoTbndsUmNjVWNGYWNJaWxYcWNyS2ZDajluTDFz/view
- https://github.com/Fadavvi/CVE-2018-17431-PoC#confirmation-than-bug-exist-2018-09-25-ticket-id-xwr-503-79437
- http://packetstormsecurity.com/files/159246/Comodo-Unified-Threat-Management-Web-Console-2.7.0-Remote-Code-Execution.html
- https://drive.google.com/file/d/0BzFJhNQNHcoTbndsUmNjVWNGYWNJaWxYcWNyS2ZDajluTDFz/view
- https://github.com/Fadavvi/CVE-2018-17431-PoC#confirmation-than-bug-exist-2018-09-25-ticket-id-xwr-503-79437
