This is for educational and authorized penetration testing only. Always test in a sandboxed environment!
UDFs allow users to add custom logic (e.g., FACTORS() , to_valid_utf8 ) to database engines. Commonly used in MySQL , Sphinx Search , and Firebird SQL . Firebird's isql Interactive SQL Utility
User-Defined Functions allow you to extend the core capabilities of search engines like Sphinx. Why Use UDFs?
666 allows global read and write access, often a vulnerability in /etc/cron.d/ or /usr/lib/ .
This resource includes common UDF payloads used to demonstrate how attackers can gain OS-level privileges via SQL injection.