CVE-2019-25429: Comodo Dome Firewall XSS Vulnerability

CVE-2019-25429 Overview

Comodo Dome Firewall 2.7.0 contains a reflected cross-site scripting (XSS) vulnerability that allows attackers to inject malicious scripts by submitting crafted input to the openvpn_advanced endpoint. Attackers can inject JavaScript code through the GLOBAL_NETWORKS and GLOBAL_DNS parameters via POST requests to execute arbitrary scripts in users' browsers.

Critical Impact

Successful exploitation enables attackers to execute arbitrary JavaScript in the context of authenticated users' sessions, potentially leading to session hijacking, credential theft, or unauthorized administrative actions on the firewall management interface.

Affected Products

• Comodo Dome Firewall 2.7.0

Discovery Timeline

• 2026-02-19 - CVE-2019-25429 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2019-25429

Vulnerability Analysis

This vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The Comodo Dome Firewall web management interface fails to properly sanitize user-supplied input before reflecting it back to the browser, creating an opportunity for script injection attacks.

The vulnerability exists in the OpenVPN configuration management functionality of the firewall's administrative interface. When administrators access the openvpn_advanced endpoint, the application processes POST request parameters without adequate input validation or output encoding. This allows an attacker who can craft a malicious link or form submission to inject arbitrary JavaScript code that executes within the security context of the victim's browser session.

Root Cause

The root cause stems from insufficient input validation and output encoding in the web application layer. The GLOBAL_NETWORKS and GLOBAL_DNS parameters accept user-controlled data that is subsequently rendered in the HTTP response without proper sanitization. The application fails to implement Content Security Policy headers or other browser-side protections that could mitigate the impact of XSS attacks.

Attack Vector

The attack requires network access to the Comodo Dome Firewall management interface and relies on user interaction. An attacker must craft a malicious URL or form that, when visited by an authenticated administrator, submits a POST request containing JavaScript payloads in the vulnerable parameters. Since this is a reflected XSS vulnerability, the malicious script is not stored on the server but is instead "reflected" back to the user's browser from the attacker-controlled input.

The attack could be delivered through phishing emails, malicious links embedded in forums, or watering hole attacks targeting network administrators. Once the victim clicks the crafted link or submits the malicious form while authenticated to the firewall interface, the injected JavaScript executes with the victim's session privileges.

Detection Methods for CVE-2019-25429

Indicators of Compromise

• Unusual POST requests to the /openvpn_advanced endpoint containing JavaScript tags or encoded script payloads
• Web server access logs showing requests with <script>, javascript:, or HTML event handlers in GLOBAL_NETWORKS or GLOBAL_DNS parameters
• Browser console errors or unexpected script execution originating from the firewall management interface
• Authentication tokens or session cookies being transmitted to external domains

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block common XSS payload patterns in POST parameters
• Configure intrusion detection systems to alert on requests containing script injection signatures targeting the openvpn_advanced endpoint
• Enable detailed access logging on the Comodo Dome Firewall management interface and monitor for suspicious parameter values
• Deploy browser-based XSS auditors or Content Security Policy violation reporting

Monitoring Recommendations

• Establish baseline traffic patterns for the firewall management interface and alert on anomalies
• Monitor for authentication events from unexpected IP addresses following suspicious HTTP requests
• Review web server logs regularly for attempts to inject HTML or JavaScript content
• Configure SIEM rules to correlate XSS attack patterns with subsequent unauthorized administrative actions

How to Mitigate CVE-2019-25429

Immediate Actions Required

• Restrict access to the Comodo Dome Firewall management interface to trusted internal networks only
• Implement network segmentation to isolate the firewall management plane from general user traffic
• Enable multi-factor authentication for administrative access if available
• Train administrators to recognize phishing attempts and avoid clicking suspicious links while authenticated

Patch Information

Organizations should consult the VulnCheck Advisory on Comodo and the Comodo Firewall product page for information regarding security updates. The Exploit-DB entry #46408 provides additional technical details about this vulnerability.

Workarounds

• Place the firewall management interface behind a VPN or bastion host to limit exposure
• Configure a reverse proxy with input sanitization capabilities in front of the management interface
• Implement strict Content Security Policy headers at the proxy level to prevent inline script execution
• Disable or restrict access to the openvpn_advanced endpoint if OpenVPN configuration is not actively needed
• Use browser extensions that block reflected XSS attacks when accessing the management interface