What is the Backdoor Factory and how does it implant backdoors into EXE files?

The Backdoor Factory (BDF) is a tool that modifies PE executable files to inject a payload and alter program execution flow. It works by either adding a new section with RWE permissions or using existing [code caves](/news/implanting-backdoors-into-exe-files-using-bdf#code-caves) within the file's sections, then patching the entry point to jump to the payload and return to normal execution. This technique allows an attacker to maintain functionality while executing a backdoor, such as a reverse shell.