Automatic translation of assembly shellcodes to printable byte codes

Abstract

The generation of printable shellcode is an important computer security research area. The original idea of the printable shellcode generation was to write a binary, executable code in a way that the generated byte code contains only bytes that are represented by the English letters, numbers and punctuation characters. In this way unfortunately only a limited number of CPU instructions can be used. In the originally published paper a small decoder is written with instructions represented by printable characters and the shellcode is decoded on the stack to be executed later. This paper, however describes a proof of concept project, which converts the source code of a full assembly program or shellcode to a new source code, whose compiled binary code contains only printable characters. The paper also presents new, printable character implementation of some CPU instructions.