This closes a string literal and a parenthetical condition in the application's original backend query.
Enforcing strict allow-lists for inputs to ensure no special characters (like quotes or hashtags) can manipulate the query logic. {KEYWORD}') UNION ALL SELECT NULL#
Attackers use NULL values to probe the database because NULL maps to almost any data type, allowing them to figure out the exact number of columns the database is expecting without triggering a data-type error. This closes a string literal and a parenthetical
Once the structure is matched, the attacker replaces the NULL with actual commands to extract sensitive data like usernames, passwords, or configuration files. 4. Defense and Mitigation {KEYWORD}') UNION ALL SELECT NULL#