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

C.
NIDS

D.
Layer 7 firewall

Explanation:
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.