This string is a classic example of a , specifically a Union-Based SQLi attack . It is used by attackers to test for vulnerabilities or extract data from a database. Breakdown of the Payload
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. {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 string is a classic example of a
: 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 represents the original search term or input field
: In some cases, these injections can be used to log in without a valid password.
: 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:
: This command tells the database to combine the results of the original query with a new "injected" query.