: NULL is used because it is compatible with almost any data type (integers, strings, dates, etc.).
: The attacker wants the database to return the results of the original query plus the results of their injected query. : NULL is used because it is compatible
: The database returns a row of empty data. The attacker now knows the table has 6 columns and can proceed to more dangerous injections, such as UNION SELECT username, password, NULL... to steal sensitive information. The attacker now knows the table has 6
: By using six NULL values, the attacker is testing if the original query has exactly six columns. This string is a classic example of a
This string is a classic example of a used by security researchers and attackers to probe a website's database for vulnerabilities.
If the page returns an error (like "The used SELECT statements have a different number of columns"), the attacker will try again with five or seven NULL values until the error disappears. 4. -- (The Comment) In SQL, double-dashes signify the start of a comment.
: Any code that was supposed to follow the input (like a closing quote or a WHERE clause) is ignored by the database, preventing syntax errors that would break the injection. 5. GoJB