Lion Cipher Lab

Understand SQL injection — and how to stop it

• AppSec / DevSecOps
• Beginner
• ~35 min
• Free · no account required

Why it matters

SQL injection is one of the oldest, most-taught, and still most damaging web vulnerabilities — the OWASP Top 10 has carried injection in every edition it has published, and in the 2025 list that category holds more recorded vulnerabilities than any other on it. Almost every course teaches it as an attack to perform. That is the wrong center of gravity for someone who wants to build and defend software: the useful skill is not entering a magic string into someone else's login box, it is understanding why the flaw exists so that you never write it, and knowing the exact defense that makes it…

What you'll learn

• what SQL injection actually is
• why string-concatenated queries are dangerous
• reading the classic ' OR '1'='1 login as a concept
• parameterized queries / prepared statements
• allow-list input validation
• least-privilege database accounts
• defense in depth for the data layer

Steps in this lab

1. What SQL injection actually is (one sentence you already understand)
2. The dangerous pattern: building a query by gluing input into a string
3. The classic example, as a concept: ' OR '1'='1
4. Why this is worth taking seriously
5. The fix that actually matters: parameterized queries
6. Defense in depth 1: validate input against an allow-list
7. Defense in depth 2: give the database account least privilege
8. The takeaway: write code that can't be injected

Open the full interactive lab →