SQL Injection (Prevention Tips)
SQL Injection is a serious security vulnerability that allows attackers to execute malicious SQL code through user input. It can lead to data theft, deletion, or even full control of the database.
🔹 What Is SQL Injection?
An attacker inserts SQL code into input fields to manipulate your queries.
-- Dangerous example:
SELECT * FROM users WHERE username = '$input' AND password = '$input';If $input is:' OR 1=1 --
The query becomes:
SELECT * FROM users WHERE username = '' OR 1=1 -- ' AND password = '';This always returns true — granting access without valid credentials!
🔒 How to Prevent It
✅ 1. Use Prepared Statements / Parameterized Queries
Safest way across all DBMS.
-- Example in PHP (PDO)
$stmt = $pdo->prepare("SELECT * FROM users WHERE username = ? AND password = ?");
$stmt->execute([$user, $pass]);✅ 2. Use ORM or Frameworks with Safe Query APIs
They escape inputs automatically.
✅ 3. Validate & Sanitize Input
Check for expected format (e.g., email, numbers), reject suspicious patterns.
✅ 4. Least Privilege for DB User
Your application DB user should have only the required permissions.
✅ 5. Avoid Dynamic SQL with Raw Input
Especially in procedures or admin tools.
🧠 Quick Recap
| Tip | Description |
|---|---|
| Use Prepared Statements | Safely bind values to SQL queries |
| Sanitize Input | Validate all user inputs |
| Least Privilege Access | Limit DB user permissions |
| Avoid Dynamic SQL | Don’t concatenate raw input in SQL strings |
| Use Secure Frameworks | Let frameworks handle escaping/queries securely |
💡 SQL Injection is preventable — always treat user input as untrusted.