If the page loads normally, the attacker knows the database is expecting 6 columns.

: The database executes: SELECT col1, col2, col3, col4, col5, col6 FROM products WHERE name = '' UNION ALL SELECT NULL,NULL,NULL,NULL,NULL,NULL--' .

: The database returns a row of empty data. The attacker now knows the table has 6 columns and can proceed to more dangerous injections, such as UNION SELECT username, password, NULL... to steal sensitive information.

: By using six NULL values, the attacker is testing if the original query has exactly six columns.

This is a SQL operator used to combine the result sets of two or more SELECT statements into a single result set.

: Any code that was supposed to follow the input (like a closing quote or a WHERE clause) is ignored by the database, preventing syntax errors that would break the injection. 5. GoJB

This string is a classic example of a used by security researchers and attackers to probe a website's database for vulnerabilities.

Scanners append strings like GoJB so that the security researcher can search the website's logs or the page's source code later to confirm that their input was successfully processed and reflected by the server. Summary of the Attack Flow