Is it possible to have a (small) shellcode with unique bytes only?
So far I noticed the smallest shellcode I can find online is 19 bytes for Linux x86, but it does repeat bytes, especially the "/" from "/bin/sh" and even some opcodes contain repeating bytes. Noticed a nice trick on x86_64 where you can
mov rax, 0xFF978CD091969DD1 ; garbage at first look neg rax ; rax = /bin/sh
But still some bytes from the opcodes repeat. Does anyone know a solution for either x86 or x86_64?