WordPress provides flexibility for website developers to publish or modify website content without using the admin login page. XML-RPC is a really useful method that helps applications such as mobile apps authenticate before performing privileged actions on the site.
However, with the WordPress XML-RPC Service, which was developed for distributed systems to communicate with each other and transfers data in XML format, Brute Force and DDoS attacks can be launched without getting caught by Web Application Firewall (WAF) and other plugins.