Web Application Firewall
A Web Application Firewall (WAF) is a security tool that monitors, filters, and blocks HTTP/HTTPS traffic to and from web applications to protect against common attacks such as SQL injection, cross-site scripting (XSS), and DDoS. It operates at the application layer (Layer 7) of the OSI model, analyzing web requests and responses to enforce security policies and mitigate threats. WAFs can be deployed as hardware appliances, software solutions, or cloud-based services, providing a critical defense mechanism for web-facing applications.
Developers should learn and use WAFs when building or maintaining web applications that handle sensitive data, such as e-commerce sites, banking platforms, or healthcare systems, to prevent data breaches and ensure compliance with security standards like PCI DSS. It is essential for mitigating OWASP Top 10 vulnerabilities, reducing the risk of application-layer attacks, and complementing other security measures like firewalls and intrusion detection systems. In cloud environments, WAFs help secure APIs and microservices by filtering malicious traffic before it reaches the application servers.