CVE-2019-25405: Comodo Dome Firewall XSS Vulnerability

CVE-2019-25405 Overview

CVE-2019-25405 is a stored cross-site scripting (XSS) vulnerability discovered in Comodo Dome Firewall version 2.7.0. The vulnerability exists in the license activation functionality, where the newLicense parameter fails to properly sanitize user input before storing and rendering it. This allows attackers to inject malicious JavaScript code that executes in the context of administrator browser sessions when they view the affected page.

Stored XSS vulnerabilities are particularly dangerous in security appliances like firewalls because they can lead to complete administrative compromise. An attacker who successfully exploits this vulnerability could steal administrator session cookies, modify firewall configurations, create backdoor accounts, or pivot to attack internal network resources.

Critical Impact

Attackers can inject persistent JavaScript payloads through the license activation endpoint, potentially compromising administrator accounts and gaining control over firewall configurations.

Affected Products

• Comodo Dome Firewall 2.7.0
• Comodo Dome Firewall (versions prior to patch availability)

Discovery Timeline

• 2026-02-19 - CVE-2019-25405 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2019-25405

Vulnerability Analysis

This stored cross-site scripting vulnerability resides in the license activation endpoint of Comodo Dome Firewall 2.7.0. The application accepts POST requests containing license information through the newLicense parameter but fails to implement adequate input validation and output encoding. When an attacker submits a crafted payload containing JavaScript code, the malicious script is stored in the application's backend and subsequently rendered without sanitization when administrators access the license management interface.

The network-accessible attack vector makes this vulnerability exploitable remotely. While user interaction is required (an administrator must view the page containing the injected payload), the persistent nature of stored XSS means the payload remains active until manually removed, increasing the likelihood of successful exploitation over time.

Root Cause

The root cause of CVE-2019-25405 is improper input validation and output encoding in the license activation functionality (CWE-79). The application fails to sanitize the newLicense parameter before storing the value and does not apply proper HTML entity encoding when displaying stored license data. This lack of defense-in-depth allows script tags and JavaScript event handlers to be executed in the browser context of users viewing the affected page.

Attack Vector

The attack is executed remotely over the network by sending a specially crafted POST request to the license activation endpoint. The attacker constructs a payload containing malicious JavaScript within the newLicense parameter value. When an administrator later accesses the license management section of the firewall interface, the stored payload executes in their browser session.

The exploitation mechanism involves:

1. Attacker identifies the license activation endpoint accepting POST requests
2. Attacker crafts a payload containing JavaScript code within the newLicense field
3. The payload is submitted and stored by the application without sanitization
4. When an administrator views the license management page, the malicious script executes
5. The attacker can then steal session tokens, modify configurations, or perform other malicious actions

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

Detection Methods for CVE-2019-25405

Indicators of Compromise

• Unexpected JavaScript code or HTML tags present in license-related database entries or log files
• Anomalous POST requests to license activation endpoints containing script tags or event handlers
• Administrator session tokens being transmitted to external domains
• Unauthorized configuration changes to firewall rules without corresponding administrator activity

Detection Strategies

• Implement web application firewall (WAF) rules to detect XSS patterns in POST parameters targeting license endpoints
• Monitor HTTP access logs for requests containing encoded script tags (<script>, %3Cscript%3E) in the newLicense parameter
• Deploy content security policy (CSP) headers and monitor for violation reports indicating script injection attempts
• Audit stored license data periodically for unexpected HTML or JavaScript content

Monitoring Recommendations

• Enable verbose logging for all administrative interface access and license-related operations
• Configure alerts for any external resource loading from the firewall management interface
• Monitor outbound connections from the firewall management interface for unusual destination domains
• Implement session monitoring to detect session token exposure or hijacking attempts

How to Mitigate CVE-2019-25405

Immediate Actions Required

• Restrict network access to the Comodo Dome Firewall management interface to trusted administrative IP addresses only
• Implement a web application firewall with XSS filtering rules in front of the management interface
• Review and audit existing license data for any potentially malicious stored content
• Enforce the use of modern browsers with built-in XSS filtering capabilities for administrator access

Patch Information

Organizations should consult Comodo directly for patch availability and upgrade guidance. The Comodo Firewall product page provides information about current product versions and support resources. Until a patch is applied, network-level access controls should be implemented to limit exposure of the vulnerable endpoint.

Workarounds

• Deploy strict Content Security Policy (CSP) headers to prevent inline script execution on the management interface
• Implement network segmentation to ensure the firewall management interface is only accessible from a dedicated management VLAN
• Use HTTP-only and Secure flags on session cookies to reduce the impact of potential session theft
• Consider deploying a reverse proxy with XSS filtering capabilities between administrators and the firewall interface

# Network access restriction example using iptables
# Restrict management interface access to trusted admin subnet only
iptables -A INPUT -p tcp --dport 443 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP

# Log suspicious requests for forensic analysis
iptables -A INPUT -p tcp --dport 443 -j LOG --log-prefix "FIREWALL-MGMT-ACCESS: "