CVE-2019-25428
📋 TL;DR
This vulnerability allows attackers to inject malicious JavaScript into Comodo Dome Firewall's web interface through crafted POST requests. When users access the vulnerable openvpn_users endpoint, the injected scripts execute in their browsers, potentially stealing session cookies or performing unauthorized actions. Organizations using Comodo Dome Firewall 2.7.0 are affected.
💻 Affected Systems
- Comodo Dome Firewall
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator session cookies, gain full administrative access to the firewall, reconfigure network security policies, or pivot to internal networks.
Likely Case
Attackers would steal session cookies to impersonate administrators, potentially modifying firewall rules or accessing sensitive configuration data.
If Mitigated
With proper input validation and output encoding, malicious scripts would be neutralized before reaching user browsers, preventing execution.
🎯 Exploit Status
Exploitation requires the attacker to trick an authenticated user into clicking a malicious link or visiting a crafted page. Public exploit code is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.8.0 or later
Vendor Advisory: https://cdome.comodo.com/firewall/
Restart Required: Yes
Instructions:
1. Log into Comodo support portal. 2. Download latest version (2.8.0+). 3. Backup current configuration. 4. Install update following vendor instructions. 5. Restart firewall services.
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rules
allDeploy WAF rules to block XSS payloads in POST parameters to /openvpn_users endpoint
Input Validation Filter
allImplement input validation to sanitize username, remotenets, explicitroutes, static_ip, custom_dns, and custom_domain parameters
🧯 If You Can't Patch
- Restrict access to 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 submitting a POST request to /openvpn_users with XSS payload in vulnerable parameters and checking if script executes in responseCheck Version:
ssh admin@firewall 'show version' or check web interface System > AboutVerify Fix Applied:
After patching, repeat the test - script payloads should be properly encoded or rejected📡 Detection & Monitoring
Log Indicators:
- POST requests to /openvpn_users containing script tags or JavaScript in parameters
- Unusual parameter values in username, remotenets, explicitroutes fields
Network Indicators:
- HTTP requests with encoded script payloads in POST data
- Multiple failed login attempts followed by XSS payload submissions
SIEM Query:
source="firewall_logs" AND url_path="/openvpn_users" AND (http_method="POST") AND (param_content CONTAINS "<script>" OR param_content CONTAINS "javascript:")