This paper is on reverse engineering backdoored binaries on an x86 Linux Operating System. It is meant for the beginner reverse engineer with some knowledge of ELF, C, x86 ASM, and Linux. We will begin by explaining the basics of our binary from what we can determine by disassembling and then we will recreate the source code for the evil part of our backdoored binary. You will need a few basic tools for this, objdump, elfsh, hexdump, a text editor. . . and your brain.