Does my site need a web application firewall?

Blocks requests matching signatures for common injection and traversal patterns, which stops most untargeted scanning before it reaches the application.

Provides virtual patching: refusing the specific request shape that exploits a newly disclosed flaw, which buys the days between disclosure and deployment.

Applies rate limiting and bot management, refusing clients that behave automatically.

Absorbs volumetric traffic at the edge when it sits in front of the origin as part of a delivery network.

Enforces protocol hygiene: refusing malformed requests, oversized headers and inconsistent length declarations before the application parses them.

Produces a log of what was attempted, which is frequently the most useful output and the least read.

Understand authorisation. A well-formed request asking for someone else's data looks entirely legitimate, and no signature matches it.

Stop an attacker who can reach the origin directly. An origin left answering at its own address makes the whole layer optional.

Fix the underlying flaw. The vulnerability remains and stays exploitable by any request the rules do not match.

Catch attacks in encoded or encrypted payloads it cannot parse, or in request shapes its rules do not anticipate.

Distinguish a customer from an attacker when both send valid requests, which is the case that matters most and the one signatures are least suited to.

False positives block real visitors. A rule matching a pattern in ordinary content — a forum post about SQL, a filename with unusual characters — refuses a legitimate request, and the visitor sees an error they cannot explain.

Tuning is ongoing work. Default rule sets are deployed in monitoring mode first for exactly this reason, and that monitoring period needs someone to read it.

Your own automation gets caught: monitoring scripts, sitemap generators, integration partners, and audit tools.

Search engine crawlers can be filtered too, which slows indexing without anything visible going wrong.

Debugging becomes harder: an intermittent 403 with no application log entry is a support thread that takes hours to trace to the edge.

An application handling payments, personal data or authenticated sessions, where the consequence of one successful request is high.

Software you cannot patch quickly — a platform with a slow release cycle, or plugins maintained by third parties.

A site that attracts targeted traffic, or one that has already been attacked.

Anywhere the operational capacity exists to tune it. An untuned firewall generating alerts nobody reads is a cost with no benefit.

Compliance or contractual requirements that name one specifically, which is a legitimate reason even where the technical case is thin.

A static site with no application behind it, where there is no request shape to exploit.

A small site whose software is current and whose dependencies are few. Patching promptly beats filtering.

Anywhere the origin remains publicly reachable, because the filter can be bypassed in one request.

VeriFixScan reports `infrastructure.waf` when a firewall is detected and `infrastructure.origin_exposure` when the origin appears reachable independently — and the second finding is what decides whether the first one is doing anything.