A WAF is a security layer that sits in front of a web application and inspects HTTP requests for signs of abuse. It can block, challenge, or log traffic based on rules for malicious patterns, unusual methods, bad payloads, or risky paths. Unlike a network firewall, a WAF understands web application behavior and is designed to protect applications, APIs, and login forms.
In cyber security, WAFs matter because many attacks begin with ordinary-looking web requests: SQL injection, cross-site scripting, path probing, or attempts to reach sensitive endpoints before authentication. In a case involving WordPress REST batch traffic, defenders may use a narrow WAF rule to block requests to paths such as /wp-json/batch/v1 or specific query forms while they patch the vulnerable code. This makes a WAF useful for reducing exposure quickly, but it is usually a temporary or layered control, not a substitute for fixing the application itself.