What is the primary function of a web application firewall in front of public-facing web apps?

• A. Logs traffic
• B. Detects and prevents web-based attacks
• C. Serves static content
• D. Replaces authentication

Answer: (B)

Web application firewalls are placed in front of public-facing apps to scrutinize HTTP(S) traffic at the application layer. Their primary function is to detect and prevent web-based attacks by applying rules and signatures that block malicious patterns—such as SQL injection, XSS, CSRF, and other common vulnerabilities—before they reach the application. They may also log activity and help with rate limiting, but their main purpose is to protect the app from harmful requests. They don’t serve static content (that’s the job of a web server or CDN) and they don’t replace authentication (that’s handled by the app or identity services), though they can work alongside those mechanisms.