A web application firewall, or WAF, is a security control that filters and monitors HTTP traffic to help protect web applications from common attacks. It matters because internet-facing applications are frequent targets for exploitation, abuse, and automated attack traffic.
What is a Web Application Firewall (WAF)?
A WAF sits in front of a web application or service and inspects incoming and sometimes outgoing web traffic for malicious patterns. It is commonly used to help block attacks such as SQL injection, cross-site scripting, bot abuse, exploit probes, and other suspicious request behavior.
WAFs can improve resilience and buy defenders time, but they are not a replacement for secure application design and remediation of underlying flaws.
What WAFs Commonly Help Block
WAFs commonly help block injection attempts, suspicious request payloads, abusive bots, exploit signatures, protocol anomalies, and certain types of automated reconnaissance against web applications.
WAF vs. Firewall
A traditional firewall focuses more on network traffic and connection rules. A WAF focuses specifically on web application traffic and application-layer patterns in HTTP or HTTPS requests.
Frequently Asked Questions
Can a WAF stop every web attack?
No. WAFs help reduce exposure, but they require tuning and do not eliminate the need for secure coding, testing, and remediation of application weaknesses.
Why do organizations deploy WAFs?
They deploy them to reduce web-app attack surface, add compensating protection, improve visibility into hostile traffic, and protect exposed applications more consistently.
