This is often a "false" or "null" value. By inputting a value that likely doesn't exist (like a negative ID), the attacker forces the application to return an empty result set or an error. This makes it easier to see how the database reacts when the injected code is added. ORDER BY 1 : This is the structural probe .
SELECT name, email FROM users WHERE id = "-5025" ORDER BY 1#";
Successful use of this payload is the first step in a larger attack. Once the number of columns is known, an attacker can use a UNION SELECT statement to: Extract usernames and passwords. Bypass authentication screens. Gain administrative access to the server. -5025 ORDER BY 1#
The ORDER BY clause tells the database to sort results by a specific column.
Attackers increment this number (e.g., ORDER BY 2 , ORDER BY 3 ). When the database throws an error (e.g., "The ORDER BY position number 10 is out of range"), the attacker knows exactly how many columns the original query is fetching. This is often a "false" or "null" value
Here is a short technical paper outlining its structure, purpose, and how to defend against it. 1. Introduction
This is the comment character for MySQL. It tells the database to ignore everything that follows it in the original code. This prevents the "leftover" part of the developer’s query from causing a syntax error that would break the injection. 3. Execution Flow ORDER BY 1 : This is the structural probe
This is the terminator . It attempts to break out of the developer's intended string literal. If the application does not sanitize input, the database engine will see this quote and assume the original command has ended, allowing the attacker to append their own logic.