what is waf in networking

A Web Application Firewall (WAF) is a type of firewall that protects web applications from common attacks, such as SQL injection, cross-site scripting (XSS), and distributed denial-of-service (DDoS) . It filters, monitors, and blocks malicious HTTP/S traffic traveling to the web application, and prevents any unauthorized data from leaving the app. A WAF can be network-based, host-based, or cloud-based, and is often deployed through a reverse proxy and placed in front of one or more websites or applications. It inspects each packet and uses a rule base to analyze Layer 7 web application logic and filter out potentially harmful traffic that can facilitate web exploits. A WAF is typically user, session, and application aware, cognizant of the web apps behind it and what services they offer. It can detect and immediately prevent several of the most dangerous web application security flaws, which traditional network firewalls and other intrusion detection systems might not be capable of doing. A WAF can be especially beneficial to a company that provides an e-commerce site, online financial services, or any other type of web-based product or service involving interactions with customers or business partners.