shellen v0.2.1: Interactive shellcoding environment to easily craft shellcodes

by do son · March 9, 2018

Shellen

Shellen is an interactive shellcoding environment. If you want a handy tool to write shellcodes, then shellen may be your friend. Also, it can be used just as assembly/disassembly tool.

It uses keystone and capstone engines for all provided operations.

Shellen works only on python3. Maybe support for python2 will appear in the future.

Features

Shellen was created for assembling and disassembling instructions, so there are two modes of using the tool: asm and dsm respectively. Of course, there are some other possibilities like syscalls tables, common shellcodes and other.

Problems/New features

If you find a problem/bug or something, then just write an issue about this problem. Also, if you think, that some feature will be nice to use in shellen, then do the same — write an issue and I will try to add this feature.

Prompt

It also has a usefull prompt, displaying current mode, OS (Operating System for syscalls) and chosen architecture exactly for this mode. It looks as follows:

L:asm:x86_32 >

You can edit your input like you’re typing in a terminal. Also, it has a history of commands (just type up arrow to see them).

L is the shortened name of Linux in the prompt. Below listed all other OS names:

L is Linux
W is Windows
M is MacOS

Assembling

To assembly instructions, type them separated by colons as follows:

L:asm:x86_32 > mov edx, eax; xor eax, eax; inc edx; int 80;

   [+] Bytes count: 7

       Raw bytes:  "\x89\xc2\x31\xc0\x42\xcd\x50"

       Hex string: "89c231c042cd50"

Disassembling

It works exactly as assembling. Type your bytes in the input prompt and see the result!

L:dsm:x86_32 > 89c231c042cd50

        0x00080000:     mov     edx, eax

        0x00080002:     xor     eax, eax

        0x00080004:     inc     edx

        0x00080005:     int     0x50

Architectures

asm and dsm modes work for different architectures. To see a list of available architectures for a current mode, type this:

Syscalls

It’s apparent that in process of crafting a shellcode you will be needed syscalls. So, shellen will help you with that. Just type sys with a name of desired syscall and shellen will show you a list of possible syscalls you were looking for.

This prints possible variants of syscall depending on entered pattern. Syscall table for searching depends on chosen architecture and OS (Operating System). In this case it’s x86_32 and Linux.

Common shellcodes

Shellen can show you a list of common shellcodes depending on your keyword. The example of using placed in Picturessection. It uses API of shell-storm.org site (thanks to the author!). You can use it like this:

L:asm:x86_32 > shell <keyword> <count>

Actually, count parameter isn’t required.

Operating Systems

It was assumed that there will be several OSs (Linux, Windows, and MacOS), but right now supported only Linux.

Changlog v0.2.1

Fixed bugs with a prompt
Added an ability to execute shellcodes
Little code fixes

Installing

$ sudo apt-get install cmake python3-dev python3-setuptools

$ sudo pip3 install shellen

Source: https://github.com/merrychap/