Protect Your Web Application with SafeLine: A Step-by-Step Guide

#webdev #safeline #waf #cybersecurity

This guide walks you through how to configure and protect a web application using SafeLine WAF.

Prerequisite

Make sure SafeLine is already installed and running.

If not, check out the installation guide first.

How SafeLine Works

SafeLine is a web application firewall (WAF) built on Nginx.

It works as an HTTP/HTTPS reverse proxy, sitting in front of your app to inspect and filter incoming traffic.

All traffic goes through SafeLine first. It blocks malicious requests and only forwards clean traffic to your backend.

Proxy an Application with SafeLine

Log in to the SafeLine Admin Console.
Go to Applications → Applications.
Click Add Application.
Fill in your app details:

Domain: Your app’s domain name or IP (e.g. www.chaitin.com)
Port: The port SafeLine should listen on (e.g. 80 or 443) For HTTPS, check the SSL option.
Upstream: The actual address (IP or domain) of your backend app

Once saved, update your DNS to point your domain to the SafeLine server's IP.

Now you can access your app through the domain — fully protected by SafeLine.

Simulate Web Attacks

To verify that SafeLine is working, try simulating some common attacks.

If your app is protected by SafeLine, test it with URLs like these (replace with your own domain):

SQL Injection

https://yourdomain.com/?id=1+and+1=2+union+select+1
XSS

https://yourdomain.com/?id=<img+src=x+onerror=alert()>
Path Traversal

https://yourdomain.com/?id=../../../../etc/passwd
Code Injection

https://yourdomain.com/?id=phpinfo();system('id')
XXE

https://yourdomain.com/?id=<?xml+version="1.0"?><!DOCTYPE+foo+SYSTEM+"">