Web application firewall
lastmod 2025-12-16created 2025-12-152 edits
A web application firewall (WAF) is a specific form of application firewall that filters, monitors, and blocks HTTP traffic to and from a web service. By inspecting HTTP traffic, it can prevent attacks that exploit known vulnerabilities of web applications, such as SQL injection, cross-site scripting (XSS), file inclusion vulnerabilities, and improper system configuration. Most major financial institutions use WAFs to help mitigate not only "zero-day" vulnerabilities in web applications but also bugs or vulnerabilities that are hard to patch, through custom attack signature strings.