Edge Security · Web Application Firewall
Cloudflare WAF. Block attacks before they land.
Stop SQL injection, cross-site scripting, and known exploit attempts at the edge, before they ever touch your application.
Cloudflare's Web Application Firewall uses managed rulesets updated continuously by their security team, covering the OWASP Top 10 and thousands of known CVE exploit signatures. We deploy, tune, and manage it for your environment.
How it works
Inspect at the edge. Block before it lands.
Traffic passes through Cloudflare's global network before reaching your server. The WAF inspects each request and acts on it in milliseconds.
Cloudflare updates the managed rulesets as new vulnerabilities are disclosed. Your application gets protection against threats that didn't exist when it was built.
Request received
An HTTP or HTTPS request arrives at Cloudflare's edge network before it ever reaches your origin server or application.
Ruleset inspection
The request is checked against Cloudflare's managed rulesets, updated continuously as new attack patterns emerge.
Threat scored
Requests that match known attack signatures are scored and either blocked, challenged, or logged depending on your configured action and confidence threshold.
Clean traffic forwarded
Legitimate requests pass through without modification or added latency. Only traffic that triggers a rule is intercepted.
What's covered
Every major attack class, blocked at the edge.
Cloudflare's managed rulesets cover the OWASP Top 10 and thousands of CVE-specific signatures, with custom rules for your application layered on top.
SQL injection
Attempts to manipulate database queries through unvalidated input fields are detected and blocked at the WAF layer before reaching your application.
Cross-site scripting
XSS payloads attempting to inject malicious scripts into your web pages are caught by signature and heuristic rules across managed rulesets.
Remote code execution
Requests attempting to execute arbitrary commands on your server through vulnerable application parameters are blocked by exploit signature rules.
Path traversal
Attempts to access files outside the web root using directory traversal sequences are blocked before reaching your application file system.
API protection
API endpoints are protected with schema validation and rate-based rules, blocking malformed requests and enumeration attempts against your API surface.
File inclusion attacks
Local and remote file inclusion attempts targeting PHP and similar server-side runtimes are caught by vulnerability-specific signatures.
Custom rules
Rules specific to your application's structure, IP allowlists, geo-restrictions, and business logic can be added alongside the managed ruleset.
Virtual patching
When a new vulnerability is disclosed publicly, a WAF rule can block exploit attempts while your development team deploys an application-level fix.
Virtual patching
When a significant vulnerability is disclosed, a zero-day in a framework you use or a new exploit for a CMS plugin, the window between disclosure and patch can be days or weeks. A WAF rule closes that window.
- WAF rules deployed in hours of a new CVE disclosure
- Application remains protected while a proper fix is developed
- Exploit attempts logged with full request detail for investigation
- Rules removed cleanly once the application patch is deployed
- No application code changes required
WAF and penetration testing
A WAF blocks known attack patterns. A penetration test finds unknown ones specific to your application. Both are necessary for applications that handle sensitive data or customer information.
- WAF covers signature-based attacks and known CVEs
- Pentest uncovers logic flaws, broken access, and custom vulnerabilities
- WAF in place before pentest narrows the exposed surface
- Pentest findings inform custom WAF rules post-engagement
- Together they address both known and unknown threats
What you gain
Attacks blocked. Application protected.
Four outcomes from Cloudflare WAF deployment, measurable from the first week of operation.
Known attacks blocked
The OWASP Top 10 and thousands of known CVE exploit signatures are blocked at the edge, before they interact with your application code.
Virtual patching
New vulnerabilities can be blocked at the WAF layer within hours of disclosure, buying time for a proper application-level fix.
Attack visibility
Every blocked request is logged with the matching rule, source IP, and request details. You can see exactly what is being attempted against your application.
Compliance supported
WAF deployment supports PCI DSS Requirement 6.4 and other frameworks that require a web application firewall in front of applications handling payment or sensitive data.
Does a WAF replace penetration testing?
No. A WAF blocks known attack patterns, signatures and known CVEs. looks for vulnerabilities specific to your application's logic, configuration, and architecture. A WAF won't find a broken access control issue in your code. Penetration testing will. They serve different purposes and both are worth having.
What is a managed ruleset?
Cloudflare maintains sets of firewall rules updated continuously as new attack patterns emerge and new CVEs are published. A managed ruleset means you don't have to write and maintain individual rules yourself. Cloudflare's security team does that work on your behalf, applied to your traffic automatically.
Will the WAF block legitimate traffic?
Some false positives are possible, particularly on applications with unusual input patterns or custom APIs. We tune the ruleset during deployment and establish a logging period before moving rules to blocking mode, which keeps false positives to a minimum. Any false positive can be addressed with a custom exception rule.
Do I need to be using Cloudflare for DNS or CDN?
To use Cloudflare WAF, your traffic needs to route through Cloudflare's network. This typically means pointing your DNS to Cloudflare and using them as a reverse proxy. Many businesses already do this. If you don't, we can walk through what the change involves. For most websites it's straightforward.
Can I write my own WAF rules?
Yes. Custom rules can be added alongside the managed ruleset to match your application's specific structure, block traffic from specific IP ranges, enforce geo-restrictions, or address business logic that managed rules don't cover. We configure and document any custom rules as part of our deployment.
Edge-layer protection for your web application
Block attacks before they reach your server.
Cloudflare WAF is one of the most effective controls available for web-facing applications. We deploy, tune, and manage it so your team doesn't have to.