SQL Injection Tester: Find and Fix Query Vulnerabilities Before Attackers Do

SQL injection remains in the OWASP Top 10 year after year because developers still concatenate user input into queries. A SQL injection tester shows you exactly how attackers exploit vulnerable queries — and generates the parameterized versions that prevent these attacks.

What Is SQL Injection Tester?

A SQL injection tester analyzes your SQL queries for injection vulnerabilities. It tests common attack patterns (UNION injection, boolean-based, time-based, stacked queries) against your query structure and shows you the parameterized alternative that neutralizes each attack vector.

How to Use SQL Injection Tester on DevToolHub

1. Open the SQL Injection Tester tool on DevToolHub — no signup required.
2. Paste your SQL query that includes user input into the input panel.
3. Mark which parts come from user input (form fields, URL params, etc.).
4. Click Test to see how common injection payloads affect the query.
5. Review the vulnerability report with severity ratings.
6. Copy the parameterized version of your query for your language/framework.

Detecting a Classic Injection

A vulnerable login query:

-- Vulnerable:
SELECT * FROM users
WHERE email = '" + userEmail + "'
  AND password = '" + userPass + "';

-- Attack input: email = ' OR '1'='1' --
-- Resulting query:
SELECT * FROM users
WHERE email = '' OR '1'='1' --'
  AND password = 'anything';
-- This returns ALL users — authentication bypassed!

The OR '1'='1' always evaluates true, and -- comments out the password check.

The Parameterized Fix

Parameterized queries separate code from data:

// Node.js with parameterized query:
const result = await db.query(
  'SELECT * FROM users WHERE email = $1 AND password = $2',
  [userEmail, userPass]
);

// Python with parameterized query:
cursor.execute(
  'SELECT * FROM users WHERE email = %s AND password = %s',
  (user_email, user_pass)
);

// The attack input becomes a literal string:
// WHERE email = ''' OR ''1''=''1'' --'
// No injection — the input is treated as data, not SQL code.

Parameters are escaped automatically by the database driver — the injection attempt becomes harmless text.

UNION Injection Detection

A more sophisticated attack that extracts data from other tables:

-- Vulnerable:
SELECT name, price FROM products WHERE id = " + productId;

-- Attack: productId = 1 UNION SELECT email, password FROM users
-- Result:
SELECT name, price FROM products WHERE id = 1
UNION
SELECT email, password FROM users;
-- Now returns all user credentials alongside product data!

UNION injection is particularly dangerous because it leaks data from any table in the database.

Pro Tips

• Always parameterize — there is no safe way to concatenate user input into SQL. Period.
• Use ORMs — Prisma, SQLAlchemy, and ActiveRecord parameterize by default; raw queries are the danger zone.
• Validate input types — a product ID should be an integer; reject anything else before it reaches SQL.
• Least privilege — database users should only have SELECT/INSERT/UPDATE on the tables they need; never use root.

When You Need This

• Auditing legacy code for SQL injection vulnerabilities
• Teaching developers about injection attacks with safe examples
• Validating that ORM-generated queries are properly parameterized
• Preparing for security audits by testing all database-touching endpoints