CVE-2019-25430
📋 TL;DR
Comodo Dome Firewall 2.7.0 contains a reflected cross-site scripting vulnerability in the vpn_users endpoint. Unauthenticated attackers can inject malicious JavaScript via crafted username parameters in POST requests, potentially compromising victim browsers. This affects all deployments running the vulnerable version.
💻 Affected Systems
- Comodo Dome Firewall
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator credentials, hijack sessions, redirect users to malicious sites, or perform actions on behalf of authenticated users.
Likely Case
Attackers would typically use this to steal session cookies or credentials from administrators who click malicious links.
If Mitigated
With proper input validation and output encoding, the vulnerability would be prevented entirely.
🎯 Exploit Status
Exploit code is publicly available on Exploit-DB, making this easy to weaponize.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.8.0 or later
Vendor Advisory: https://cdome.comodo.com/firewall/
Restart Required: Yes
Instructions:
1. Download the latest version from Comodo's website. 2. Backup current configuration. 3. Install the update following vendor instructions. 4. Restart the firewall service.
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rules
allImplement WAF rules to block malicious script patterns in username parameters.
Input Validation Filter
allAdd input validation to reject username parameters containing script tags or JavaScript patterns.
🧯 If You Can't Patch
- Restrict access to the firewall management interface to trusted IP addresses only.
- Implement Content Security Policy (CSP) headers to prevent script execution from untrusted sources.
🔍 How to Verify
Check if Vulnerable:
Test by sending a POST request to /vpn_users with a username parameter containing a simple script payload like <script>alert('test')</script> and checking if it executes.Check Version:
Check the firewall web interface or CLI for version information; should show 2.8.0 or higher.Verify Fix Applied:
After patching, repeat the test with the same payload; the script should not execute and should be properly sanitized.📡 Detection & Monitoring
Log Indicators:
- POST requests to /vpn_users with script-like content in username parameters
- Unusual JavaScript execution in firewall logs
Network Indicators:
- HTTP traffic containing script payloads in POST data to the firewall management interface
SIEM Query:
source="firewall_logs" AND method="POST" AND uri="/vpn_users" AND username CONTAINS "<script>"