SQL Injection (SQLi) has been around for decades, yet it’s still one of the most common and dangerous web vulnerabilities in 2025. If your app talks to a database, chances are you’ve worried about SQLi at some point.
So I decided to put an open source Web Application Firewall (WAF) to the test:
👉 SafeLine WAF
It claims to block SQLi and other web attacks out of the box. But does it really work? Let’s find out.
Setting Up a Vulnerable Target
For testing, I spun up DVWA (Damn Vulnerable Web Application) — a deliberately insecure PHP app that’s perfect for practicing attacks.
Here’s a simple query inside DVWA:
SELECT first_name, last_name FROM users WHERE user_id = '$id';
When you input 1, the app returns the first user. But what if we give it something malicious?
Simulating an SQL Injection Attack
I entered this payload:
1' UNION SELECT 1, database() #
And boom — it worked. The page returned the current database name. That means DVWA is vulnerable, and an attacker could dig much deeper.
Enter SafeLine WAF
Now, let’s route DVWA traffic through SafeLine WAF.
Setup is quick:
- Deploy with Docker
- Add your site as an upstream
- Point traffic through SafeLine’s reverse proxy
I tried the same injection payload again:
1' UNION SELECT 1, database() #
✅ Blocked.
Instead of leaking database info, SafeLine intercepted the request and showed a generic error page. The attack never reached the backend.
Logs and Visibility
Inside the SafeLine dashboard, the request shows up as a SQL Injection attempt with full details logged.
This is crucial for developers — not only is the attack blocked, but you also get visibility into what was attempted.
Why This Matters
Most dev teams don’t have time to manually sanitize every single input or review every query. A WAF adds a critical safety net:
- Blocks zero-day payloads even if your app has a coding flaw
- Prevents automated scanners from mapping your site
- Gives you monitoring and logs for security events
Even if your app isn’t 100% secure, a WAF buys you time and protection.
Final Thoughts
SafeLine WAF isn’t just “yet another firewall.” It’s:
- Free & open source (no license needed)
- Developer-friendly (Docker/K8s support, quick deploy)
- Smart detection (semantic analysis, not just regex rules)
For small teams, indie projects, or anyone running a web service in 2025, this is a serious security upgrade at zero cost.
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