Introduction This paper assumes a working knowledge of basic shellcoding techniques, and x86 assembly, I will not rehash these in this paper. I hope to teach you some of the lesser known shellcoding techniques that I have picked up, which will allow you to write smaller and better shellcodes. I do not claim to have invented any of these techniques, except for the one that uses the div instruction. The multiplicity of mul This technique was originally developed by Sorbo of darkircop.net. The mul instruction may, on the surface, seem mundane, and it's purpose obvious. However, when faced with the difficult challenge of shrinking your shellcode, it proves to be quite useful. First some background information on the mul instruction itself. mul performs an unsigned multiply of two integers. It takes only one operand, the other is implicitly specified by the %eax register. So, a common mul instruction might look something like this: movl $0x0a,%eax mul $0x0a This wou