CompTIA Security+ Question B-44

Which of the following devices is BEST suited to protect an HTTP-based application that is susceptible to injection attacks?

A. Protocol filter
B. Load balancer
D. Layer 7 firewall

Answer: D

An application-level gateway firewall filters traffic based on user access, group membership, the application or service used, or even the type of resources being transmitted. This type of firewall operates at the Application layer (Layer 7) of the OSI model.