SQL Injection Explained: How User Input Can Hijack Database Queries

SQL injection is a cyberattack technique where user-supplied input manipulates a database query's structure instead of remaining harmless data. The vulnerability arises when applications build SQL queries by directly concatenating user input into the query string, erasing the boundary between data and executable commands. An attacker can exploit this by entering SQL syntax characters that alter the query's logic, potentially bypassing authentication or accessing sensitive data. The reliable fix is to use parameterized queries or prepared statements, which keep the SQL structure and user-supplied values entirely separate throughout execution. Most modern ORMs and query builders apply this separation automatically, making safe database interaction the default for developers.