: Once the column count is known, they replace the NULL values with actual commands (e.g., version() , user() , or table_name ) to steal sensitive information.
: Confirm that the application is vulnerable to SQL injection. {KEYWORD} UNION ALL SELECT NULL,NULL,NULL,NULL-- Uizf
If you found this in a "complete report" (such as a security scan or a web server log), it indicates that an automated tool or a manual actor has the system. : Once the column count is known, they
: This is a SQL comment symbol. It tells the database to ignore the rest of the original, legitimate query, effectively "breaking" the intended logic to execute the injected code. {KEYWORD} UNION ALL SELECT NULL,NULL,NULL,NULL-- Uizf