A Web Application Firewall (WAF) is a special type of firewall that protects specifically to web applications. It is deployed in front of web applications and analyzes bi-directional web-based (HTTP) traffic - detecting and blocking anything malicious. WAFs use a combination of rule-based logic, parsing, and signatures to detect and prevent attacks such as cross-site scripting and SQL injection. This functionality can be implemented in software or hardware, running in an appliance device, or in a typical server running a common operating system. It may be a stand-alone device or integrated into other network components.
