DefenseCode ThunderScan SAST Advisory: WordPress Booking Calendar Multiple Security Vulnerabilities Advisory ID: DC-2017-12-005 Advisory Title: WordPress Booking Calendar Plugin Multiple Vulnerabilities Advisory URL: http://www.defensecode.com/advisories.php Software: WordPress Booking Calendar plugin Language: PHP Version: 7.0/7.1 and below Vendor Status: Vendor contacted, updates released Release Date: 2017/12/13 Risk: Medium 1. General Overview =================== During the security audit of Booking Calendar plugin for WordPress CMS, multiple vulnerabilities were discovered using DefenseCode ThunderScan application source code security analysis platform. More information about ThunderScan is available at URL: http://www.defensecode.com 2. Software Overview ==================== Booking Calendar plugin - described by the authors as the ultimate booking system for online reservation and availability checking service for your site. According to wordpress.org, it has more than 40,000 active installs. Homepage: https://wordpress.org/plugins/booking/ http://wpbookingcalendar.com/ https://wordpress.org/plugins/booking/#developers 3. Vulnerability Description ============================ During the security analysis, ThunderScan discovered SQL injection and Local file inclusion vulnerabilities in Booking Calendar WordPress plugin. The easiest way to reproduce the SQL injection vulnerabilities is to send the specified parameter to the provided URL while being logged in as administrator or another user that is authorized to access the plugin settings page. Users that do not have full administrative privileges could abuse the database access the vulnerabilities provide to either escalate their privileges or obtain and modify database contents they were not supposed to be able to. By requesting a specially crafted URL, the attacker can cause remote server to execute a php file of his choosing. Although the user requesting the URL has to be logged into the WordPress administrative console, the attacker can cause the administrator to request such a URL by using various social engineering/phishing approaches. Specified file will be interpreted by php interpreter, and any valid php code will indeed be executed. If the php installation on server has "allow_url_include=1" configuration option set, this attack can be expanded to execute a php file from any remote URL. If the php version is less than 5.3.4, the ".php" that gets appended to the end of the file name attacker chose can be omitted by adding a null character ("%00") to the requested URL, and enable the attacker to execute any file, regardless of the extension. Due to the CSRF token needed to perform the attack the risk is lowered to medium. 3.1. SQL injection Function: $wpdb->query() Variable: $_POST[ "booking_id" ]; Vulnerable URL: /wp-admin/admin-ajax.php File: booking\lib\wpbc-ajax.php --------- 152 $booking_id = $_POST[ "booking_id" ]; 153 $approved_id = explode('|',$booking_id); ... 162 $approved_id_str = join( ',', $approved_id); ... 165 if ( false === $wpdb->query( $wpdb->prepare( "UPDATE {$wpdb->prefix}bookingdates SET approved = %s WHERE booking_id IN ({$approved_id_str})", $is_approve_or_pending ) ) ){ --------- 3.2. SQL injection Function: $wpdb->query() Variable: $_POST[ "booking_id" ]; Vulnerable URL: /wp-admin/admin-ajax.php Vulnerable code snippets: File: booking\lib\wpbc-ajax.php --------- 110 $id_of_new_bookings = $_POST[ "booking_id" ]; 111 $arrayof_bookings_id = explode('|',$id_of_new_bookings); ... 114 wpbc_update_number_new_bookings( $arrayof_bookings_id, $is_new , $user_id ); --------- File: booking\lib\wpdev-booking-functions.php --------- 1468 function wpbc_update_number_new_bookings( $id_of_new_bookings, $is_new = '0' , $user_id = 1 ){ ... 1485 $update_sql = "UPDATE {$wpdb->prefix}booking AS bk SET bk.is_new = {$is_new} WHERE bk.booking_id IN ( {$id_of_new_bookings} ) "; ... 1487 if ( false === $wpdb->query( $update_sql ) ) { --------- 3.3 PHP file inclusion Function: include() Variable: $_POST['captcha_chalange'] Vulnerable URL: /wp-admin/admin-ajax.php Vulnerable code snippets: File: booking\core\lib\wpbc-booking-new.php --------- 127 if (! wpbc_check_CAPTCHA( $_POST['captcha_user_input'], $_POST['captcha_chalange'], $bktype ) ) { ... 19 function wpbc_check_CAPTCHA( $the_answer_from_respondent, $prefix, $bktype ) { ... 23 $correct = $captcha_instance->check($prefix, $the_answer_from_respondent); --------- File: wp-content\plugins\booking\js\captcha\captcha.php --------- 139 function check( $prefix, $response ) { ... 141 include( $this->tmp_dir . $prefix . '.php' ); --------- 4. Solution =========== Vendor resolved the security issues. All users are strongly advised to update WordPress Booking Calendar plugin to the latest available version. 5. Credits ========== Discovered by Neven Biruski using DefenseCode ThunderScan source code security analyzer. 6. Disclosure Timeline ====================== 2016/11/15 Vulnerabilities discovered 2017/04/04 Vendor contacted 2017/04/04 Vendor responded - 7.0 already fixed SQL injection vulns 2017/04/04 Update released for LFI (7.1) 2017/12/13 Advisory released to the public 7. About DefenseCode ==================== DefenseCode L.L.C. delivers products and services designed to analyze and test web, desktop and mobile applications for security vulnerabilities. DefenseCode ThunderScan is a SAST (Static Application Security Testing, WhiteBox Testing) solution for performing extensive security audits of application source code. ThunderScan SAST performs fast and accurate analyses of large and complex source code projects delivering precise results and low false positive rate. DefenseCode WebScanner is a DAST (Dynamic Application Security Testing, BlackBox Testing) solution for comprehensive security audits of active web applications. WebScanner will test a website's security by carrying out a large number of attacks using the most advanced techniques, just as a real attacker would. Subscribe for free software trial on our website http://www.defensecode.com/ . E-mail: defensecode[at]defensecode.com Website: http://www.defensecode.com Twitter: https://twitter.com/DefenseCode/