SQL injection is a code injection method, used to attack data-driven applications. This vulnerability allows a hacker to submit crafted input to interfere with the application’s interaction with back-end databases. A hacker may be able to obtain arbitrary data from the application, interfere with its logic, or execute commands on the database server itself.
SQL is an interpreted language, and web applications commonly create SQL statements that include user-supplied data. If this is done in an insecure way, the application will become vulnerable to SQL injection. This vulnerability is one of the most famous vulnerabilities that affect web applications. In the most serious cases, It can allow an anonymous hacker to read and change all data stored within the database, and even gain full control of the server on which the database is running.
Many modern applications avoid this vulnerability by using APIs that, if correctly used, are intrinsically safe against SQL injection attacks. It typically occurs in the occasional cases where these defense mechanisms cannot be applied.
Discovering SQL injection is sometimes a difficult job, requiring persistence to locate the one or two instances in an application where the typical controls have not been applied. As this trend has developed, methods for finding and exploiting SQL injection flaws have evolved, using more subtle indicators of vulnerabilities, and more refined and powerful exploitation techniques.
The key to avoid being a victim of the SQL injection vulnerability is to control and validate user input.