What is SQL Injection?
SQL Injection (SQLi) is a code injection technique that exploits vulnerabilities in an application's software by inserting malicious SQL queries into input fields. It is a form of attack that allows an attacker to manipulate a database by executing arbitrary SQL code, potentially leading to unauthorized data access, database modification, or even complete database compromise.
How Does SQL Injection Work?
SQL injection occurs when an application does not properly sanitize user input. For instance, when a web application uses unsanitized input from users to construct SQL queries, an attacker might input a specially crafted string that alters the intended execution of the query. This means the attacker can bypass authentication, view sensitive data, or alter records within the database.
Types of SQL Injection
- In-band SQL Injection: The attacker uses the same communication channel to both launch the attack and gather results.
- Blind SQL Injection: The attacker asks the database true or false questions and determines the response based on different application behaviors.
- Out-of-band SQL Injection: The attacker uses different channels to receive data from the database, usually useful when in-band is not possible.
Prevention
To mitigate SQL injection risks, developers should implement strong input validation, use prepared statements or parameterized queries, and regularly update and patch their database management systems. Security best practices and regular code reviews can also significantly lower the chances of SQL vulnerabilities.