CVE-2019-25402: Comodo Dome Firewall XSS Vulnerability

CVE-2019-25402 Overview

CVE-2019-25402 is a reflected Cross-Site Scripting (XSS) vulnerability affecting Comodo Dome Firewall version 2.7.0. This vulnerability allows unauthenticated attackers to inject malicious scripts by submitting crafted input to the username parameter on the login endpoint. Attackers can leverage this flaw to execute arbitrary JavaScript in users' browsers by sending specially crafted POST requests containing script payloads in the username field.

Critical Impact

Unauthenticated attackers can execute arbitrary JavaScript in victim browsers, potentially leading to session hijacking, credential theft, or further attacks against firewall administrators.

Affected Products

• Comodo Dome Firewall 2.7.0

Discovery Timeline

• 2026-02-19 - CVE-2019-25402 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2019-25402

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The flaw exists within the authentication mechanism of Comodo Dome Firewall 2.7.0, specifically in how the login page processes and reflects user-supplied input.

When a user submits credentials to the login endpoint, the application fails to properly sanitize the username parameter before reflecting it back to the user's browser. This lack of input validation allows attackers to inject HTML and JavaScript code that executes within the context of the victim's browser session. The vulnerability is exploitable over the network and requires user interaction, as the victim must click on a malicious link or submit a crafted form.

Root Cause

The root cause of this vulnerability is inadequate input sanitization and output encoding in the login functionality of Comodo Dome Firewall 2.7.0. The application does not implement proper server-side validation or HTML entity encoding for user-supplied data in the username parameter before including it in the HTTP response. This oversight allows script tags and other malicious HTML elements to be injected and rendered by the victim's browser as legitimate page content.

Attack Vector

The attack leverages a network-based vector requiring user interaction. An attacker crafts a malicious URL or POST request containing JavaScript code embedded within the username parameter. When an unsuspecting user is tricked into submitting this request (typically via a phishing link or embedded form), the malicious script executes in their browser within the security context of the Comodo Dome Firewall web interface.

This can enable attackers to steal session cookies, capture credentials entered in the login form, redirect users to malicious sites, or perform actions on behalf of authenticated administrators if they are subsequently logged in. Since the firewall management interface is the target, successful exploitation could provide attackers with a foothold into security infrastructure management.

Technical details and proof-of-concept information are documented in the Exploit-DB #46408 advisory and the VulnCheck Comodo Dome Advisory.

Detection Methods for CVE-2019-25402

Indicators of Compromise

• Unusual POST requests to the Comodo Dome Firewall login endpoint containing script tags or JavaScript event handlers in the username field
• HTTP logs showing encoded characters such as %3Cscript%3E or HTML entities in authentication parameters
• Browser console errors or unexpected script execution warnings when accessing the firewall login page
• Reports of phishing links targeting the firewall management interface URL

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block XSS patterns in POST request parameters targeting the login endpoint
• Implement network intrusion detection signatures for common XSS payloads directed at Comodo Dome Firewall infrastructure
• Monitor HTTP access logs for requests containing suspicious characters or encoded script content in the username parameter
• Utilize SentinelOne Singularity platform to detect browser-based attacks and malicious script execution on endpoints accessing the firewall interface

Monitoring Recommendations

• Enable detailed logging for all authentication attempts on the Comodo Dome Firewall management interface
• Configure SIEM rules to alert on potential XSS patterns in web server logs associated with firewall management access
• Implement Content Security Policy (CSP) monitoring where possible to detect inline script execution attempts
• Regularly review access patterns to the firewall administrative interface for anomalies

How to Mitigate CVE-2019-25402

Immediate Actions Required

• Restrict access to the Comodo Dome Firewall management interface to trusted networks and IP addresses only
• Implement a reverse proxy or WAF with XSS filtering capabilities in front of the firewall management interface
• Educate administrators about phishing attacks that may attempt to exploit this vulnerability
• Monitor for any vendor updates or patches from Comodo addressing this vulnerability

Patch Information

No official patch information was available in the CVE data at the time of publication. Organizations should consult the official Comodo Firewall product page for the latest security updates and firmware versions. Contact Comodo support directly to inquire about remediation options for this vulnerability.

Workarounds

• Implement network-level access controls to limit management interface access to specific trusted IP addresses or VPN connections only
• Deploy a web application firewall (WAF) or reverse proxy configured to filter XSS attack patterns before requests reach the firewall interface
• Use browser security extensions that block inline script execution when accessing the management interface
• Consider disabling or restricting web-based management until a patch is available, using alternative management methods such as CLI or dedicated management networks

# Example: Restrict management interface access using iptables
# Allow only trusted admin subnet to access firewall management port
iptables -A INPUT -p tcp --dport 443 -s 10.0.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP