CVE-2025-31100: Mojoomla School Management RCE Flaw

CVE-2025-31100 Overview

CVE-2025-31100 is an Unrestricted Upload of File with Dangerous Type vulnerability in the Mojoomla School Management WordPress plugin. This vulnerability allows authenticated attackers to upload a web shell to the web server, potentially leading to complete server compromise. The flaw stems from improper file type validation during the upload process, enabling malicious actors to bypass security controls and execute arbitrary code on the target system.

Critical Impact

Attackers with low-level authentication can upload malicious PHP web shells to gain persistent remote code execution capabilities on affected WordPress installations.

Affected Products

• Mojoomla School Management WordPress Plugin versions up to and including 1.93.1 (02-07-2025)
• WordPress installations running vulnerable versions of the School Management plugin

Discovery Timeline

• 2025-08-31 - CVE-2025-31100 published to NVD
• 2025-09-02 - Last updated in NVD database

Technical Details for CVE-2025-31100

Vulnerability Analysis

This vulnerability is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). The School Management plugin fails to properly validate file types during upload operations, allowing attackers to upload files with executable extensions such as .php. Once uploaded, these malicious files can be accessed directly through the web server, enabling remote code execution.

The attack can be performed by authenticated users, which in WordPress environments can include subscribers, contributors, or other low-privilege user roles depending on the plugin's configuration. The scope of the vulnerability extends beyond the vulnerable component, potentially impacting the entire WordPress installation and underlying server infrastructure.

Root Cause

The root cause of this vulnerability lies in inadequate file upload validation within the School Management plugin. The plugin does not implement sufficient checks to verify that uploaded files are restricted to safe, non-executable file types. This may include missing or bypassable MIME type validation, lack of file extension whitelist enforcement, or improper handling of file contents that allows attackers to disguise executable code.

Attack Vector

The attack is network-based and requires low-privilege authentication to exploit. An attacker can exploit this vulnerability by:

1. Authenticating to the WordPress installation with any valid user credentials
2. Navigating to a file upload functionality within the School Management plugin
3. Uploading a malicious PHP file (web shell) by bypassing weak file type restrictions
4. Accessing the uploaded web shell directly via its URL path
5. Executing arbitrary commands on the server with the privileges of the web server process

The exploitation does not require user interaction and has the potential to affect resources beyond the vulnerable component's security scope, enabling attackers to pivot to other systems or access sensitive data across the entire server.

Detection Methods for CVE-2025-31100

Indicators of Compromise

• Presence of unexpected PHP files in WordPress upload directories, particularly within plugin-specific folders
• Web server logs showing POST requests to upload endpoints followed by GET requests to unusual file paths
• Newly created files with suspicious names or obfuscated PHP code in /wp-content/uploads/ or plugin directories
• Unusual outbound network connections originating from the web server process

Detection Strategies

• Monitor file system changes in WordPress upload directories for newly created PHP or other executable files
• Implement web application firewall (WAF) rules to detect and block web shell upload attempts
• Review access logs for patterns indicating file upload followed by direct script access
• Deploy endpoint detection solutions to identify post-exploitation activities such as reverse shells or command execution

Monitoring Recommendations

• Enable detailed logging for all file upload operations within WordPress
• Configure intrusion detection systems to alert on suspicious file creations in web-accessible directories
• Implement file integrity monitoring on WordPress installations to detect unauthorized changes
• Set up alerts for unusual process spawning from web server processes (e.g., www-data user executing shell commands)

How to Mitigate CVE-2025-31100

Immediate Actions Required

• Update the Mojoomla School Management plugin to the latest patched version immediately
• Audit WordPress upload directories for any suspicious or unknown PHP files and remove them
• Review user accounts and remove any unauthorized or suspicious users from the WordPress installation
• Consider temporarily disabling the School Management plugin until a patch is applied if updates are not immediately available

Patch Information

Refer to the Patchstack WordPress Vulnerability Advisory for official patch information and remediation guidance from the vendor. Ensure you are running a version of the School Management plugin newer than 1.93.1 that addresses this arbitrary file upload vulnerability.

Workarounds

• Implement server-level restrictions to prevent execution of PHP files in upload directories using .htaccess or web server configuration
• Restrict user registration and access to only trusted accounts until the vulnerability is patched
• Deploy a web application firewall with rules to block file uploads containing PHP or other executable content
• Consider network segmentation to limit the potential impact of a successful exploitation

# Apache .htaccess configuration to prevent PHP execution in uploads directory
# Place this file in wp-content/uploads/ directory
<FilesMatch "\.(?:php|phar|phtml|php[0-9])$">
    Require all denied
</FilesMatch>