DLL injection is a technique used in programming and hacking to run code within another process by injecting a dynamic-link library (DLL). This method is commonly utilized for legitimate purposes such as debugging, modifying functionalities, or enhancing features. However, it can also be misused for malicious purposes, such as creating unauthorized access to a system or application. Tools designed for DLL injection enable developers to test, analyze, and modify the behavior of a program without altering its original code. Understanding DLL injection and using it wisely can open doors to advanced programming possibilities and insights into software behavior.