Metasm is a cross-architecture assembler, disassembler, linker, and debugger. It is written in such a way that it is easy to add support for new architectures. For now, the following architectures are in:

  • Intel Ia32.txt (16 and 32bits)

  • Intel X86_64.txt (aka Ia32 64bits, X64, AMD64)

  • MIPS

  • PowerPC

  • Sh4

Supports low and high-level debugging support (Ia32 only for now) under Windows, Linux and remote (via a gdbserver). Metasm is included in Metasploit by default.

  • Install Metasm gem

    gem install metasm

    More about installation here.

Converting Assembly to Op-code - metasm-shell.rb

You can find metasm-shell in ruby gems default path after installation. In my case, it's located in /var/lib/gems/2.1.0/gems/metasm-1.0.2/samples

  • Run it

ruby metasm-shell.rb
type "exit" or "quit" to quit
use ";" for newline


as you can see you are now in the shell's prompt

  • Find assembly op-code

asm> nop nop
asm> call [eax]
asm> push esp
asm> pop eax

Note: it is possible to do exactly the same thing with a metasploit embedded tool: nasm_shell.

$ /opt/metasploit/tools/exploit/nasm_shell.rb
nasm > jmp esp
00000000  FFE4              jmp esp

Last updated