WAF

A WAF (Web Application Firewall) is a security layer that inspects every HTTP request to a website and filters or blocks malicious patterns before they reach the application. It defends against the OWASP Top 10 attack classes (SQL injection, cross-site scripting, file inclusion, broken authentication abuse), credential-stuffing bots, scrapers, and known exploit signatures. Modern WAFs are usually delivered as a managed cloud service (Cloudflare, AWS WAF, Imperva, Sucuri) rather than as on-server software, so updates and rule sets are continuously improved without changes to your app. Many CDNs bundle a WAF into their security offering.

How it works

A WAF applies a set of rules (vendor-managed plus custom) to every request: block known bad payloads, rate-limit suspect IPs, challenge browsers that look automated, and log everything for inspection. The strongest WAFs combine rule sets with machine-learning models trained on attack traffic.

Why it matters

A WAF is the cheapest serious upgrade to a site's security posture, defending against attacks that a fresh-installed WordPress or unpatched library is vulnerable to. It does not replace good code, but it buys time when a vulnerability is discovered and absorbs the constant background noise of internet-wide attack traffic.

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