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

If this payload successfully returns a blank page instead of an error, it confirms to a tester that the application is vulnerable. From there, they can replace the NULL s with commands to extract sensitive data, such as: Usernames and passwords. Database version and configuration details. The entire contents of specific tables. How to Prevent It

: This treats user input as data, not as executable code. {KEYWORD}) UNION ALL SELECT NULL,NULL,NULL,NULL,NULL,NULL#

: Only allow expected characters and formats. If this payload successfully returns a blank page

: 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 The entire contents of specific tables

: 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.

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

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