: This attempts to "break out" of the developer’s intended code by closing a data field and a function.

The text ') UNION ALL SELECT NULL,NULL...-- is a malicious payload used to test for vulnerabilities in a database.

If a website is vulnerable to this, an attacker doesn't just stop at NULL . They eventually replace those NULL s with commands to extract sensitive info—like your —and display them right on the screen where the "Keyword" results should have been. How Developers Stop This

: This is the heart of the attack. It tells the database to combine the results of the original (legitimate) search with a new set of data the attacker wants to see.