{keyword}') Union All Select Null,null,null,null,null,null,null,null-- Mxyc [ Pro ]

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 The text ') UNION ALL SELECT NULL,NULL

: Attackers use NULL to figure out exactly how many columns the original database table has. If the number of NULL s matches the columns, the page loads; if not, it crashes. How Developers Stop This : Attackers use NULL

: 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. It tells the database to combine the results

It looks like you've included a in your request. In the world of cybersecurity, that specific snippet is a classic example of an "Union-based" attack.