What is SQL Injection?
SQL injection happens when an attacker tricks your website into running malicious SQL code, usually by entering sneaky commands into forms or URLs. If your site isn’t protected, attackers can read, modify, or even delete your database data.
How to Protect Your Website
1. Use Prepared Statements (Parameterized Queries)
This is the #1 defense.
Instead of building SQL queries by gluing together strings (which is risky), use prepared statements with placeholders for user input.
Example (PHP with PDO):
$stmt = $pdo->prepare('SELECT * FROM users WHERE email = ?');
$stmt->execute([$user_email]);
This keeps user input separate from your SQL commands—so even if someone tries to inject malicious code, it won’t work.
2. Use ORM Libraries
Frameworks and ORMs (like Laravel’s Eloquent, Django ORM, or Ruby on Rails’ ActiveRecord) handle query building for you, automatically escaping user input and preventing injection.
3. Validate and Sanitize User Input
Don’t trust anything users enter.
- Validation: Make sure the data is what you expect (e.g., an email address, a number).
- Sanitization: Remove or escape potentially harmful characters.
But remember: validation and sanitization are defensive layers—never a substitute for parameterized queries.
4. Limit Database Privileges
Follow the principle of least privilege:
- The database user your website uses should have only the permissions needed (e.g., just SELECT, INSERT, UPDATE, and DELETE—not DROP TABLE or administrative privileges).
5. Error Handling
Don’t show raw database errors to users—they can reveal your query structure and help attackers refine their attacks.
- Display generic error messages to users.
- Log detailed errors privately for your own debugging.
6. Keep Software Updated
Always update your CMS, plugins, frameworks, and database systems. Security patches often fix vulnerabilities (including those related to SQL injection).
7. Use a Web Application Firewall (WAF)
A WAF can detect and block many common SQL injection attempts before they even reach your website code.
Quick Checklist
- Always use prepared statements (parameterized queries)
- Validate and sanitize all user inputs
- Limit database privileges for your web app
- Hide detailed error messages from the public
- Keep all software and plugins up to date
- Use a WAF for extra protection
In summary:
SQL injection is a serious threat, but the good news is that it’s entirely preventable with careful coding and good security practices. Use prepared statements everywhere, validate input, and keep your software updated—these small steps make a big difference in keeping your website (and your users) safe.
