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

: In some cases, these injections can be used to log in without a valid password.

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

: 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. : In some cases, these injections can be

: This represents the original search term or input field. The attacker appends the malicious code to this keyword. It tells the database to ignore the rest

: The attacker is attempting to determine the number of columns returned by the original database query. By adding NULL values until the page loads without an error, they can identify the table's structure.

: This command tells the database to combine the results of the original query with a new "injected" query.

If you found this in a "complete report" (such as a security scan or a web server log), it indicates that an automated tool or a manual actor has the system.