What component of Azure protects web applications from common vulnerabilities?

The Azure Web Application Firewall (WAF) is specifically designed to protect web applications from common vulnerabilities, such as SQL injection, cross-site scripting (XSS), and other exploits that can be used to compromise the integrity and availability of web apps. WAF operates at the application layer (Layer 7) of the Open Systems Interconnection (OSI) model, which allows it to inspect and filter HTTP/S traffic intended for the web application.

By employing pre-configured rules and custom rules, WAF effectively monitors incoming web traffic and can block malicious requests while allowing legitimate traffic to pass through. This proactive security measure ensures that the web applications remain secure against a variety of threats.

In contrast, the other options serve different purposes: Azure Virtual Network facilitates networking and connectivity, Azure Active Directory manages identity and access, and Azure Load Balancer distributes incoming network traffic to ensure high availability of applications. None of these components are focused specifically on protecting web applications from vulnerabilities in the way WAF does.