Privilege Escalation with MySQL User Defined Functions by Nairuz Abulhul

Functions are a block of queries and statements that take inputs and return values. All popular database systems provide a wide range of built-in functions to perform operations and tasks related to their systems. Sometimes, there is a need to create custom functions that are not available through the built-in functions to perform specific operations. Relational database systems provide that flexibility and the mechanism to allow users to create their custom functions and run them natively the same way as the built-ins; they are called User Defined Functions (UDF). UDF functions are language agnostic; they are written in any programming language to be compiled natively into a shared library. Usually, the steps involve writing a library, either a shared object in Linux, or DLL in Windows, putting that library into a system directory, then creating the SQL functions. These functions can be modified independently, and stored in the database for....