How SafeLine WAF Blocks Attacks Without Rules

Recently, a friend deployed an open-source CMS for their company. It’s powerful but naturally raises some security concerns — what if a critical vulnerability is suddenly exposed?

The safest move? Add a Web Application Firewall (WAF). But most of the well-known WAFs out there are expensive. That’s when we discovered SafeLine WAF — a high-performance, open-source option that blew us away.

What Makes SafeLine Different?

SafeLine is the world’s first WAF to use intelligent semantic analysis instead of relying on traditional rule-based detection. It learns attack patterns through automated traffic modeling, meaning:

• No need to manually maintain rulesets
• Fast response to unknown 0days
• Extremely low false positive and false negative rates

It famously blocked the Struts2 0day back in 2017 without any updates — and continues to evolve.

SafeLine is built on Nginx and works as a reverse proxy. It inspects and filters HTTP traffic between the web and your applications, protecting against:

• SQL Injection
• XSS
• Command Injection
• RCE, XXE, SSRF
• Path Traversal
• Brute-force, Crawlers, HTTP Flood
• File Upload Exploits
• … and more.

Quick Deployment Guide

Here’s how easy it is to get started.

Minimum Requirements:

• OS: Linux
• Arch: x86_64 (must support ssse3) or ARM64
• Docker: v20.10.14+
• Docker Compose: v2.0.0+
• Resources: 1 CPU / 1 GB RAM / 5 GB Disk

One-Click install command:

bash -c "$(curl -fsSLk https://waf.chaitin.com/release/latest/manager.sh)" -- --en

After installation, you'll get the admin panel address and default credentials. Open port 9443 in your browser to access it.

To reset your admin password anytime:

docker exec safeline-mgt resetadmin

Configuration Steps

1. Log in to the panel.
2. Add a new "Application" (i.e., your website).
3. In “Upstream Server”, enter your backend site’s URL.
4. Leave HTTPS unchecked if you don’t use SSL.

1. Use * for domains if none is configured.

Now just visit your IP + port to access the protected site!

Attack Testing: Does It Work?

We ran a bunch of tests, including:

• ✅ SQL Injection (classic & encoded payloads)
• ✅ File Upload bypasses
• ✅ XXE & Path Traversal
• ✅ HTTP flood
• ✅ Directory brute-force attempts

All of them were blocked, logged, and analyzed.

Built-in Log & AI Analysis

SafeLine provides a clean backend log viewer with deep packet inspection.

• Type of attack
• Risk level
• Vulnerability logic
• Recommended action

You can even enable access authentication — forcing users to log in before accessing the site.

Why SafeLine WAF?

• It’s free for personal use — even includes rule updates!

• Easy to deploy with Docker
• Fast to configure and manage
• Perfect for developers, students, or small businesses
• Strong enough for enterprise-grade protection

For security competitions or student teams acting as Blue Teams for the first time, SafeLine is the most practical tool you can get. Lightweight, powerful, and cost-effective.

Join the SafeLine Community

• 🌐 GitHub Repository
• 📚 Official Docs
• 💬 Discord Community

For questions, feedback, or sharing use cases, join the official community group! The core team is active and responsive.

SafeLine WAF is not just another open-source WAF — it’s a modern take on web security. If you're looking for an advanced, rule-free, and free-to-use solution, SafeLine is worth your time.