If a website's search bar or URL parameter isn't properly "sanitized," an attacker can use this method to: (e.g., MySQL, PostgreSQL). Extract table names and column structures.
This is the gold standard. Instead of building a query string with user input, you use placeholders ( ? ). The database treats the input strictly as data, never as executable code. If a website's search bar or URL parameter
The attacker isn't trying to delete data yet; they are trying to "fingerprint" the database. Instead of building a query string with user
The snippet you provided is a classic example of an attack. The attacker isn't trying to delete data yet;
like usernames, hashed passwords, or emails. How to Prevent It
It uses functions like CONCAT and GROUP BY to intentionally trigger a duplicate-key error. The database's error message will then "leak" the information hidden inside the query (in this case, the results of the SELECT 1 or version info) back to the attacker's screen.
Only allow the types of characters you expect. If a user is searching for a "Keyword," they probably don't need to use parentheses or semicolons.