The string you provided is a classic example of a used for a "UNION-based" attack. The "Anatomy" of the Payload
If you are seeing this on your own website logs or search bar, it means someone (or an automated bot) is testing your site for security holes. To prevent this: The string you provided is a classic example
: The attacker uses NULL to match the number of columns in the original query without causing a data type error. The string in the middle is a "fingerprint"—if the word "ZZTyernefl" appears on the website, the attacker knows the injection worked and exactly which column displays data on the screen. The string in the middle is a "fingerprint"—if
: This command tells the database to combine the results of the original (legitimate) search with a second search created by the attacker. The string you provided is a classic example