CVE-2024-6366: Profile Builder Auth Bypass Vulnerability

CVE-2024-6366 Overview

CVE-2024-6366 is a critical Unrestricted File Upload vulnerability affecting the User Profile Builder WordPress plugin developed by Cozmoslabs. The vulnerability exists in versions prior to 3.11.8 and allows unauthenticated users to upload media files via the async upload functionality of WordPress due to improper authorization checks.

Critical Impact

Unauthenticated attackers can upload arbitrary files to vulnerable WordPress installations, potentially leading to complete site compromise, remote code execution, and data exfiltration.

Affected Products

• Cozmoslabs Profile Builder (User Profile Builder plugin) versions prior to 3.11.8
• WordPress installations using vulnerable versions of the plugin

Discovery Timeline

• 2024-07-29 - CVE-2024-6366 published to NVD
• 2025-05-30 - Last updated in NVD database

Technical Details for CVE-2024-6366

Vulnerability Analysis

This vulnerability is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). The User Profile Builder plugin fails to implement proper authorization controls on file upload functionality, specifically within the async upload mechanism inherited from WordPress core. This allows unauthenticated users to bypass security restrictions and upload files to the server without proper authentication.

The vulnerability enables attackers to exploit the asynchronous upload functionality that WordPress provides for media handling. Under normal circumstances, this functionality should be restricted to authenticated users with appropriate permissions. However, the vulnerable versions of User Profile Builder expose this capability to unauthenticated visitors, creating a significant attack surface.

Root Cause

The root cause of CVE-2024-6366 lies in the absence of proper authorization checks within the plugin's file upload handling code. The plugin leverages WordPress's async upload functionality but fails to verify that the requesting user has the necessary permissions to perform file uploads. This missing authorization check allows any visitor to the site to interact with the upload endpoint as if they were an authenticated user with upload privileges.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no user interaction or prior authentication. An attacker can exploit this vulnerability by sending crafted HTTP requests directly to the vulnerable async upload endpoint. The attack can be performed remotely from any location with network access to the target WordPress installation.

The exploitation process involves:

1. Identifying a WordPress site running a vulnerable version of User Profile Builder
2. Sending malicious upload requests to the async upload endpoint
3. Bypassing authorization checks due to the missing validation
4. Successfully uploading arbitrary files to the target server

Depending on the server configuration and uploaded file types, attackers may be able to upload PHP web shells or other malicious scripts, potentially achieving remote code execution on the underlying web server. For detailed technical information, refer to the WPScan Vulnerability Report.

Detection Methods for CVE-2024-6366

Indicators of Compromise

• Unexpected files appearing in WordPress upload directories (wp-content/uploads/)
• Presence of PHP files or other executable scripts in media upload folders
• Unusual HTTP POST requests to async-upload.php from unauthenticated sessions
• Web server logs showing suspicious upload activity from unknown IP addresses

Detection Strategies

• Monitor web server access logs for POST requests to /wp-admin/async-upload.php that lack valid authentication cookies
• Implement file integrity monitoring on WordPress upload directories to detect unauthorized file additions
• Deploy web application firewall (WAF) rules to detect and block suspicious file upload attempts
• Scan existing upload directories for unexpected file types, particularly PHP or executable files

Monitoring Recommendations

• Configure real-time alerting for new file creations in WordPress upload directories
• Implement logging and monitoring for all HTTP requests to WordPress admin endpoints
• Regularly audit installed plugin versions against known vulnerability databases
• Enable SentinelOne Singularity to monitor for post-exploitation behaviors such as web shell execution

How to Mitigate CVE-2024-6366

Immediate Actions Required

• Update User Profile Builder plugin to version 3.11.8 or later immediately
• Audit WordPress upload directories for any suspicious or unauthorized files
• Review web server access logs for evidence of exploitation attempts
• Consider temporarily disabling the plugin if immediate patching is not possible

Patch Information

Cozmoslabs has addressed this vulnerability in User Profile Builder version 3.11.8. WordPress administrators should update to this version or later through the WordPress admin dashboard or by downloading the latest version from the official WordPress plugin repository. After updating, verify the plugin version by navigating to Plugins → Installed Plugins in the WordPress admin panel.

Workarounds

• Implement web application firewall rules to block unauthenticated requests to async-upload.php
• Restrict access to WordPress admin directories at the web server level using IP allowlisting
• Disable file uploads entirely if the functionality is not required for your site
• Configure server-side restrictions to prevent execution of uploaded files in media directories

# Apache .htaccess configuration to prevent PHP execution in uploads directory
# Add this to wp-content/uploads/.htaccess

<FilesMatch "\.php$">
    Require all denied
</FilesMatch>

# Nginx equivalent configuration
# Add to server block
location ~* /wp-content/uploads/.*\.php$ {
    deny all;
}