{keyword}') Union All Select Null,null,null,null,null,null,null-- Hofz -

: This is the core of the attack. It tells the database to combine the results of the legitimate query with the results of a new, malicious one.

: This is a SQL comment. It tells the database to ignore everything that follows it (like the original developer's remaining code), which prevents the rest of the legitimate query from causing a syntax error. : This is the core of the attack

: The attacker uses NULL values to figure out how many columns are in the original database table. If the number of NULL s doesn't match the number of columns in the original query, the database will return an error. It tells the database to ignore everything that

: A WAF can often block these types of patterned attacks automatically. : A WAF can often block these types

Are you seeing this in your , or are you testing the security of your own code ?

: This part attempts to "break out" of a standard SQL query. It uses a closing quote and parenthesis to terminate whatever the original developer intended the query to do.