SQL Injection: A Study of Attacks and Prevention Techniques

SQL injection is a database security vulnerability in which untrusted application input changes the meaning of an SQL statement. The vulnerability occurs when an application allows user-controlled values to become part of query structure rather than treating them only as data. A successful attack can expose confidential information, alter records, or enable unauthorized database access. This paper reviews the causes, consequences, attack classifications, detection approaches, and prevention techniques associated with SQL injection. The literature indicates that no single detection or prevention mechanism addresses every attack condition. Static analysis, runtime validation, automated testing, and behavior-oriented detection address different stages of the problem, while parameterized queries provide the central application-level defense. Input validation, carefully designed stored procedures, controlled error handling, and least-privilege database accounts provide additional protection