Eventually, every website ends up receiving traffic that it does not intend to accept.You may notice automated programs copying your content, multiple login attempts from unknown IP addresses, tools checking for security weaknesses on your website, or individuals intentionally looking for vulnerabilities in your application.
If this unwanted activity is not addressed, it can cause your website to perform more slowly, use up more server resources, and make your site more vulnerable to being attacked successfully.
What Are Cloudflare Custom WAF Rules
One of the easiest and most efficient methods to stop unwanted requests early is by using Cloudflare Custom WAF Rules. Rather than allowing every request to reach your hosting server, Cloudflare examines each incoming request at its global network of edge servers. When a request matches a rule you set up, Cloudflare can take immediate action by:
- Blocking the request completely
- Presenting the visitor with a CAPTCHA or JavaScript challenge
- Recording the request for review and analysis
This approach helps prevent threats from getting closer to your main server infrastructure, often stopping them before they even reach your origin system.
How Custom WAF Rules Work in Practice
If you've ever seen a page that looks like a Cloudflare challenge screen, you've already used Custom WAF Rules.
Cloudflare evaluates the request against your defined rules, determines the appropriate action, and either allows the traffic, challenges the user, or blocks it right away.
These are the 2 top most scurity features in Cloudflare
1. Managed Challenge (Security Verification Page)
A Managed Challenge is a security process used by Cloudflare to check if someone visiting a website is a real person or an automated bot.Instead of stopping the request right away, Cloudflare evaluates the situation by looking at various factors, including how the browser behaves, the reputation of the IP address, the device being used, and past activity.
If more information is needed, the visitor might be asked to do a quick check, like clicking a box that says "Verify you are human." Most genuine users finish this check quickly and can then continue using the website as usual. Please refer snapshot attched below for the understanding.
Example Usecase Implementation
If someone keeps trying to access your login page from an unusual IP address, Cloudflare can show them a Managed Challenge instead of blocking them right away.If the person passes the verification, they will be allowed access.If they fail, their request will be rejected.
2. What is the Block Action
The Block action is the most restrictive response available in Cloudflare Custom WAF Rules. When a request matches a rule that uses the Block action, Cloudflare stops the request right away, preventing it from reaching your origin server. The visitor sees a message that says "Sorry, you have been blocked," which means access to the website has been denied. Unlike the Managed Challenge, the visitor cannot verify their identity or keep browsing.
Please refer to the attached snapshot for better understanding. You may encounter this type of screen occasionally during your regular web browsing.
Example Usecase Implementation
If your server logs indicate multiple exploit attempts from the same IP address, you can set up a Custom WAF Rule to block that IP.Any subsequent requests from this address will be automatically rejected, and the visitor will be directed to the Cloudflare block page.
