Pass values as parameters

How to do it

Use placeholders such as $1, ? or %s in the driver or query builder. Placeholders hold values only. Table names, column names and sort directions cannot be parameters, so map them from a fixed allow-list in code. ORMs are safe until you pass input to their raw SQL functions. The SQL injection rule shows the attack this stops.

Example

// Bad
db.query(`SELECT id FROM customers WHERE email = '${email}'`);
// Good
db.query('SELECT id FROM customers WHERE email = $1', [email]);

# Bad
cursor.execute(f"SELECT id FROM customers WHERE email = '{email}'")
# Good
cursor.execute("SELECT id FROM customers WHERE email = %s", (email,))

// Good in PHP with PDO
$statement = $pdo->prepare('SELECT id FROM customers WHERE email = ?');
$statement->execute([$email]);

How to check

Search the code for SQL built with string joins or template strings that hold variables. None remain.