NASM Negative Jump (jump Backwards)

If you need to jump backwards to reach to your shellcode, we can use nasm_shell from msf to demonstrate.

Lets say we want to jump backwards 100 bytes (0x64) bytes, we first need to open the nasm_shell with following command below

msf-nasm_shell

You type the follow command:

nasm > jmp short -100
00000000  EB9A              jmp short 0xffffff9c

I hope that helps 😉