ShellCat

A small C++ utility for concatenating two shellcode binaries into a single executable shellcode blob.
It generates a bootstrap stub that first calls ShellcodeA, then ShellcodeB, and finally returns to the caller.

Overview

The program:

1. Loads two shellcode files (ShellcodeA and ShellcodeB) from disk.
2. Builds a small bootstrap code stub that ensures proper stack setup and execution flow.
   • On x64, the stub adjusts RSP, calls ShellcodeA, realigns the stack, then calls ShellcodeB.
   • On x86, the stub simply calls ShellcodeA then ShellcodeB.
3. Concatenates the bootstrap + ShellcodeA + ShellcodeB into one final binary.
4. Saves the resulting shellcode into FinalShellcode_x86.bin (or FinalShellcode_x64.bin depending on target).
5. Uses VirtualProtect to make the memory executable and runs the final shellcode.

Build

Compile with MSVC (x86 or x64):

Notes

• Uses VirtualProtect to mark the concatenated shellcode as executable.
• The bootstrap code ensures stack alignment before transferring control.

Disclaimer

This project is for educational and research purposes only. Do not use it for malicious activity. The author assumes no responsibility for improper use.