CVE-2019-25402 Overview
CVE-2019-25402 is a reflected cross-site scripting (XSS) vulnerability in Comodo Dome Firewall 2.7.0. The flaw resides in the login endpoint, where the username parameter is reflected back to the browser without proper output encoding. Unauthenticated attackers can craft a malicious link or form submission containing JavaScript in the username field. When a victim submits the crafted request, the payload executes in the victim's browser session. The issue is categorized under CWE-79 (Improper Neutralization of Input During Web Page Generation).
Critical Impact
Attackers can execute arbitrary JavaScript in administrator browsers, enabling session theft, credential harvesting, and unauthorized firewall configuration changes via the authenticated user's privileges.
Affected Products
- Comodo Dome Firewall 2.7.0
- Comodo Dome Firewall login interface (username POST parameter)
- Deployments exposing the management web interface to untrusted networks
Discovery Timeline
- 2026-02-19 - CVE-2019-25402 published to NVD
- 2026-02-20 - Last updated in NVD database
Technical Details for CVE-2019-25402
Vulnerability Analysis
The vulnerability exists in the authentication handler of the Comodo Dome Firewall web management console. The application accepts a username parameter via POST request to the login endpoint and reflects the supplied value into the rendered HTML response without sanitization or context-aware encoding. Because the reflection occurs server-side and renders inside an HTML or script context, attacker-supplied markup executes when the response loads in a browser.
Reflected XSS in a firewall administration interface carries elevated impact. The management console controls perimeter security policy, so script execution in an administrator session can pivot into rule modification, log access, or credential capture. Network-based exploitation requires only that a victim click an attacker-prepared link or submit a crafted form pointing at the vulnerable appliance.
Root Cause
The root cause is missing output encoding on the username parameter before it is written into the login page response. The application trusts client-supplied input and emits it into HTML without applying HTML entity encoding or content-security controls.
Attack Vector
Exploitation requires user interaction. An attacker constructs a POST request to the Dome Firewall login URL with a JavaScript payload in the username field. Delivery typically uses a phishing email containing an auto-submitting HTML form or a malicious page that triggers the request when visited. Once the victim's browser submits the form, the firewall reflects the payload and the script executes under the appliance's origin.
No authentication is required to trigger the reflection. Full technical reproduction steps are documented in the Exploit-DB #46408 entry and the VulnCheck Comodo XSS Advisory.
Detection Methods for CVE-2019-25402
Indicators of Compromise
- POST requests to the Dome Firewall login endpoint containing <script>, onerror=, javascript:, or URL-encoded equivalents inside the username parameter
- Unexpected outbound connections from administrator browsers to attacker-controlled domains shortly after visiting external links
- Web server logs showing oversized or HTML-encoded values in the username POST field
Detection Strategies
- Inspect HTTP request bodies sent to the Dome Firewall management interface for script tags and common XSS payload patterns
- Deploy a web application firewall rule that blocks reflective HTML metacharacters in authentication parameters
- Correlate failed login events with anomalous Referer headers pointing to untrusted origins
Monitoring Recommendations
- Forward Dome Firewall access logs to a centralized logging platform for retrospective searches across the username field
- Alert on administrator session activity originating immediately after a login POST containing suspicious payloads
- Monitor browser endpoints used to administer network appliances for unexpected script execution or token exfiltration
How to Mitigate CVE-2019-25402
Immediate Actions Required
- Restrict access to the Dome Firewall management interface to a dedicated administrative VLAN or jump host
- Require administrators to access the appliance from a hardened browser profile that is not used for general web browsing
- Apply any vendor-supplied updates beyond Comodo Dome Firewall 2.7.0 that address the login parameter handling
Patch Information
No vendor advisory URL is listed in the CVE record. Administrators should consult Comodo Firewall Overview and contact the vendor directly to confirm patch availability or upgrade paths beyond version 2.7.0.
Workarounds
- Place the management interface behind a reverse proxy that enforces a strict Content-Security-Policy and strips HTML metacharacters from request bodies
- Block external access to the firewall management port at the network perimeter and require VPN access for administration
- Train administrators to avoid clicking links to the firewall management URL from email or external sources
# Example iptables rule restricting management access to a trusted admin subnet
iptables -A INPUT -p tcp --dport 10443 -s 10.10.50.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 10443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
