CVE-2025-9415: Njtech Greencms RCE Vulnerability

CVE-2025-9415 Overview

A vulnerability was identified in GreenCMS up to version 2.3.0603 that allows unrestricted file upload through improper access control in the media administration module. This affects the file /index.php?m=admin&c=media&a=fileconnect, where manipulation of the upload[] parameter enables attackers to upload arbitrary files to the server. The attack can be carried out remotely by authenticated users, potentially leading to remote code execution if malicious scripts are uploaded.

Critical Impact

Authenticated attackers can exploit this unrestricted file upload vulnerability to upload malicious files, potentially achieving remote code execution on the affected GreenCMS server. This vulnerability affects an unsupported product version with no official patch available.

Affected Products

• GreenCMS up to version 2.3.0603
• Njtech GreenCMS (all versions up to 2.3.0603)

Discovery Timeline

• 2025-08-25 - CVE-2025-9415 published to NVD
• 2025-12-31 - Last updated in NVD database

Technical Details for CVE-2025-9415

Vulnerability Analysis

This vulnerability stems from insufficient input validation and improper access control (CWE-284) combined with unrestricted file upload capabilities (CWE-434) in the GreenCMS media administration module. The affected endpoint /index.php?m=admin&c=media&a=fileconnect fails to properly validate or restrict the types of files that can be uploaded through the upload[] parameter.

When an authenticated user submits a file upload request to the vulnerable endpoint, the application does not adequately verify the file type, extension, or content. This allows attackers to bypass any intended restrictions and upload potentially dangerous files, including PHP scripts or web shells, which could then be executed on the server.

The vulnerability is particularly concerning because the exploit methodology has been publicly disclosed, increasing the likelihood of exploitation in the wild. Additionally, this product is no longer supported by its maintainer, meaning no official security patch will be released.

Root Cause

The root cause of this vulnerability is twofold: improper access control (CWE-284) and unrestricted file upload (CWE-434). The GreenCMS media module lacks proper validation mechanisms to restrict uploaded file types, allowing authenticated users to upload any file type regardless of its potential danger. The application fails to implement server-side checks for file extensions, MIME types, or file content, relying instead on insufficient or absent client-side controls.

Attack Vector

The attack can be executed remotely over the network by any authenticated user with access to the admin panel. An attacker would craft a malicious HTTP POST request to the vulnerable endpoint, including a weaponized file (such as a PHP web shell) in the upload[] array parameter. Upon successful upload, the attacker could then access the uploaded file directly through the web server, achieving arbitrary code execution.

The vulnerability is exploited by sending a multipart form-data request to the fileconnect action within the media controller, with the upload[] parameter containing the malicious payload. The lack of file type restrictions means the server will accept and store the file without validation.

Detection Methods for CVE-2025-9415

Indicators of Compromise

• Unusual HTTP POST requests to /index.php?m=admin&c=media&a=fileconnect with suspicious file uploads
• Presence of unexpected PHP files or web shells in the GreenCMS upload directories
• Web server logs showing access to recently uploaded executable files in media storage locations
• Anomalous admin panel activity from unauthorized IP addresses

Detection Strategies

• Monitor web application firewall (WAF) logs for requests containing file upload payloads to the affected endpoint
• Implement file integrity monitoring on GreenCMS upload directories to detect unauthorized file additions
• Review Apache/Nginx access logs for POST requests to /index.php with m=admin&c=media&a=fileconnect parameters
• Deploy endpoint detection rules to identify web shell signatures in uploaded content

Monitoring Recommendations

• Enable detailed logging for all file upload operations in GreenCMS
• Configure alerts for any new PHP files created in web-accessible directories
• Implement network monitoring to detect outbound connections from the web server that may indicate a compromised web shell
• Regularly audit user accounts with admin panel access to identify unauthorized accounts

How to Mitigate CVE-2025-9415

Immediate Actions Required

• Restrict access to the GreenCMS admin panel to trusted IP addresses only
• Disable the media upload functionality if not required for business operations
• Implement web application firewall rules to block suspicious file uploads to the affected endpoint
• Consider migrating to a supported CMS platform as GreenCMS is no longer maintained

Patch Information

No official patch is available for this vulnerability as GreenCMS is no longer supported by its maintainer. Organizations using GreenCMS should strongly consider migrating to an actively maintained content management system. For additional technical details, refer to the GitHub Issue on CVE and VulDB entry #321258.

Workarounds

• Implement strict web server configuration to prevent execution of uploaded files in media directories
• Add server-side file type validation using .htaccess rules or equivalent web server configurations
• Restrict the fileconnect action by adding authentication checks and file extension whitelists at the web server level
• Deploy a reverse proxy with content filtering capabilities to inspect and block malicious file uploads

# Apache .htaccess configuration to prevent PHP execution in upload directories
# Place this file in the GreenCMS upload directory
<FilesMatch "\.(php|php3|php4|php5|phtml)$">
    Require all denied
</FilesMatch>

# Alternative: Disable script execution entirely in upload directories
Options -ExecCGI
RemoveHandler .php .php3 .php4 .php5 .phtml