SQL Injection Attack

What is SQL Injection ?

SQL Injection (SQLi) is a type of cyber attack that exploits vulnerabilities in web applications that use Structured Query Language (SQL). It involves injecting malicious SQL code into a website or application to manipulate the database and gain unauthorized access to sensitive data.


SQL Injection can be classified into three major categories:

1. In-band (Classic) SQL Injection

This type of attack is the most common and involves using the same channel to inject malicious SQL code and retrieve the results. There are two subtypes of in-band SQL Injection: Error-based and Union-based.

2. Inferential (Blind) SQL Injection

In this type of attack, the attacker does not receive any feedback from the application about the success or failure of the attack, making it more difficult to detect. Blind SQL Injection can be further classified into two subtypes: Boolean-based and Time-based.

3. Out-of-band SQL Injection

This type of attack involves using a different channel, such as email or DNS, to retrieve the results of the attack. This technique relies on the database server's ability to make DNS or HTTP requests to deliver data to the attacker.


SQL Injection attacks can be prevented by implementing several security measures. Here are some of the best practices to prevent SQL Injection attacks:

  • Input Validation and Sanitization
    All user input, including form fields, cookies, and hidden fields, should be validated and sanitized to ensure that it contains only valid data and doesn't contain any malicious code.
  • Least Privilege
    Database user accounts should be assigned the least amount of privileges necessary to perform their tasks. This can help prevent attackers from using stolen credentials to gain access to sensitive data.
  • Using Stored Procedures
    Stored procedures can be used to limit the amount of SQL code that is exposed to the user input. By encapsulating the SQL code in stored procedures, you can ensure that the user input is properly validated and sanitized before it is executed.
  • Using Prepared Statements
    Prepared statements can be used to separate the SQL code from the user input. This can prevent SQL Injection attacks by ensuring that the user input is properly formatted and doesn't contain any malicious code.

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