{keyword} Union All Select — Null,null,null,null-- Uizf

: This represents the original search term or input field. The attacker appends the malicious code to this keyword.

: 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: {KEYWORD} UNION ALL SELECT NULL,NULL,NULL,NULL-- Uizf

: Confirm that the application is vulnerable to SQL injection. : This represents the original search term or input field

: This command tells the database to combine the results of the original query with a new "injected" query. {KEYWORD} UNION ALL SELECT NULL,NULL,NULL,NULL-- Uizf

: 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.