: Confirm that the application is vulnerable to SQL injection.

: 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.

: This is likely a random string used as a unique identifier or "signature" to help the attacker find their specific test result in a large log file or report. Purpose of Such a Payload Attackers use this technique to:

: 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.