CVE-2024-9942: WordPress Gym Management System RCE Flaw

CVE-2024-9942 Overview

The WPGYM - WordPress Gym Management System plugin for WordPress contains a critical arbitrary file upload vulnerability due to missing file type validation in the MJ_gmgt_user_avatar_image_upload() function. This vulnerability affects all versions up to and including 67.1.0, allowing unauthenticated attackers to upload malicious files to the affected site's server, potentially leading to remote code execution.

Critical Impact

Unauthenticated attackers can exploit this vulnerability to upload arbitrary files, including PHP web shells, enabling complete server compromise and remote code execution without any authentication requirements.

Affected Products

• WPGYM - WordPress Gym Management System versions up to and including 67.1.0
• Mojoomla WordPress Gym Management System plugin for WordPress
• WordPress sites running vulnerable versions of the WPGYM plugin

Discovery Timeline

• 2024-11-23 - CVE-2024-9942 published to NVD
• 2024-11-26 - Last updated in NVD database

Technical Details for CVE-2024-9942

Vulnerability Analysis

This vulnerability is classified as CWE-434 (Unrestricted Upload of File with Dangerous Type). The MJ_gmgt_user_avatar_image_upload() function in the WPGYM plugin fails to implement proper file type validation when processing user avatar uploads. This oversight allows attackers to bypass intended security restrictions and upload files with any extension, including executable PHP scripts.

The critical nature of this vulnerability stems from the fact that it requires no authentication to exploit. An unauthenticated attacker can craft a malicious request to the vulnerable endpoint and upload a web shell or other malicious payload directly to the server. Once uploaded, the attacker can access the malicious file via a direct URL request, resulting in arbitrary code execution with the permissions of the web server process.

Root Cause

The root cause of this vulnerability lies in the absence of file type validation within the MJ_gmgt_user_avatar_image_upload() function. The function processes uploaded files without verifying that they are legitimate image files (such as JPG, PNG, or GIF). Without checks for file extensions, MIME types, or file content validation, the upload mechanism blindly accepts any file type submitted through the avatar upload functionality.

WordPress plugins handling file uploads should implement multiple layers of validation including extension whitelisting, MIME type verification, and content inspection to prevent malicious file uploads.

Attack Vector

The attack vector is network-based and requires no user interaction or authentication. An attacker can exploit this vulnerability by sending a specially crafted HTTP POST request to the avatar upload endpoint with a malicious file payload. The vulnerable function processes the upload without restriction, storing the file in a web-accessible directory.

The exploitation process typically involves: identifying WordPress sites using the WPGYM plugin, crafting a multipart/form-data request containing a PHP web shell disguised as an avatar upload, submitting the request to the vulnerable endpoint, and then accessing the uploaded malicious file to execute arbitrary commands on the server.

For detailed technical analysis of this vulnerability, refer to the Wordfence Vulnerability Report.

Detection Methods for CVE-2024-9942

Indicators of Compromise

• Unexpected PHP files in WordPress upload directories, particularly in avatar or user-related upload paths
• Web server access logs showing POST requests to WPGYM avatar upload endpoints with unusual file extensions
• New or modified PHP files in /wp-content/uploads/ directories with recent timestamps
• Outbound network connections originating from the web server process to unknown destinations
• Suspicious process spawning from PHP or web server processes indicating command execution

Detection Strategies

• Monitor file system changes in WordPress upload directories for newly created executable files
• Implement web application firewall (WAF) rules to inspect multipart file uploads for malicious content
• Deploy endpoint detection and response (EDR) solutions to identify suspicious process behavior
• Review web server access logs for POST requests containing PHP extensions in file upload parameters
• Use file integrity monitoring to detect unauthorized changes to web-accessible directories

Monitoring Recommendations

• Enable detailed logging for all file upload operations in WordPress
• Configure alerts for new PHP files created in upload directories
• Monitor for unusual HTTP POST requests to /wp-admin/admin-ajax.php with WPGYM-related action parameters
• Track web shell indicators such as base64-encoded payloads or common web shell function calls

How to Mitigate CVE-2024-9942

Immediate Actions Required

• Update the WPGYM - WordPress Gym Management System plugin to a patched version if available from the vendor
• If no patch is available, consider temporarily disabling the WPGYM plugin until a fix is released
• Audit upload directories for any suspicious files that may have been uploaded before mitigation
• Implement web application firewall rules to block malicious file uploads targeting the vulnerable endpoint
• Review web server and WordPress logs for evidence of exploitation attempts

Patch Information

Users should check the CodeCanyon product page for the latest version and security updates from Mojoomla. Apply any available patches immediately as this vulnerability allows unauthenticated remote code execution. Monitor the Wordfence Vulnerability Report for updates on patch availability and additional mitigation guidance.

Workarounds

• Disable the avatar upload functionality by removing or restricting access to the MJ_gmgt_user_avatar_image_upload function
• Implement server-level file upload restrictions to only allow image file extensions
• Use .htaccess rules to prevent PHP execution in upload directories
• Deploy a WAF rule to block requests to the vulnerable endpoint until patching is possible

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

<FilesMatch "\.(?:php|phtml|php3|php4|php5|php7|phps)$">
    Require all denied
</FilesMatch>

# Alternative: Disable script execution entirely
php_flag engine off