💉 SQL Injection — Defense, Detection & Safe Testing SQLi is a vulnerability where untrusted input manipulates database queries. Left unchecked it can expose sensitive data, modify records, or allow full database control — so treat it as a high-priority risk. The strongest prevention is parameterized queries / prepared statements and avoiding string concatenation when building SQL. Apply server-side validation (use whitelists when possible), enforce least-privilege for DB accounts, and never run