What type of threat does a Web Application Firewall (WAF) specifically protect against?

A Web Application Firewall (WAF) is specifically designed to protect web applications from a variety of threats associated with internet traffic, particularly aimed at applications that are exposed to the web. The primary role of the WAF is to filter, monitor, and analyze HTTP traffic to and from a web application, defending against attacks such as SQL injection, cross-site scripting (XSS), and other types of cyber threats targeting web applications.

Malicious web traffic can vary in form and intent, often being crafted to exploit vulnerabilities in applications. WAFs employ rules and heuristics to detect and block such traffic before it reaches the application itself. This capability is essential for maintaining the application’s integrity, confidentiality, and availability by preventing these common web-based threats.

While the other options describe potential security concerns, they fall outside the specific remit of what a WAF protects against. Network worms, physical damage to hardware, and unauthorized software installations involve different layers of security that require different solutions, such as antivirus software, physical security controls, or other network security measures.