The string -4215) UNION ALL SELECT 34,34# is a classic example of a payload. If you are looking for academic papers or technical resources related to how these attacks work, their prevention, or their history, here are several foundational and interesting papers: 🛡️ Fundamental Papers on SQL Injection
Use UNION ALL SELECT 34,34 to merge a dummy row into the original query results. This helps an attacker determine the number of columns required for a successful data dump. -4215) UNION ALL SELECT 34,34#
If you want to practice or learn about this in a controlled environment: The string -4215) UNION ALL SELECT 34,34# is
(ACM Digital Library).
by Halfond, Viegas, and Orso (IEEE Xplore). or their history