: This is the most effective defense.
: This is the "injection" part. It tells the database to append a second result set (containing the number 34 ) to the first (empty) result set. If the page then displays "34", the attacker knows the site is vulnerable and that they can use this spot to extract sensitive data like usernames or passwords. -1697 UNION ALL SELECT 34#
To prevent these types of attacks, developers should never insert user input directly into SQL queries. Instead, you should use: : This is the most effective defense
: These can block common "UNION ALL" patterns before they ever reach your database. it only receives a number.
: Ensure that if a field expects a number, it only receives a number.