{keyword}) Union All Select Null,null,null,null,null,null# Now

: This is the core of the attack. The UNION operator combines the results of two or more SELECT statements into a single result set. ALL ensures that duplicate rows are kept.

To protect your application from this type of attack, you should avoid building queries using simple string concatenation. Instead, use:

: This part attempts to "break out" of the existing SQL command. The closing parenthesis ) is used to close a function or a nested query that the developer originally intended. {KEYWORD}) UNION ALL SELECT NULL,NULL,NULL,NULL,NULL,NULL#

The string you provided is a specific used to test for vulnerabilities in a database. It is designed to trick a web application into running a second, unauthorized query and appending the results to the original one. Breakdown of the Payload

: Most modern frameworks like Hibernate or Entity Framework handle this protection automatically. : This is the core of the attack

: This treats user input as data, not as executable code.

: In MySQL, the hash symbol marks the rest of the line as a comment . This effectively deletes any remaining parts of the original developer's code (like a trailing WHERE clause or a closing quote) that would otherwise cause a syntax error. Why This Matters To protect your application from this type of

: Only allow expected characters and formats.