niernen.py

import random

# Color codes
RED = "\033[1;31m"
GREEN = "\033[1;32m"
RESET = "\033[0;0m"


# Encode shellcode using XOR, ADD, SUB, ROL, and ROR
def encode_shellcode(shellcode, key):
    encoded_shellcode = bytearray()
    for i, byte in enumerate(shellcode):
        
        # XOR
        xored_byte = byte ^ key[i % len(key)]

        # ADD
        added_byte = (xored_byte + key[(i + 1) % len(key)]) % 256

        # SUB
        subbed_byte = (added_byte - key[(i + 2) % len(key)]) % 256

        # ROL
        rolled_byte = ((subbed_byte << 1) | (subbed_byte >> 7)) % 256

        # ROR
        ror_byte = ((rolled_byte >> 1) | (rolled_byte << 7)) % 256

        encoded_shellcode.append(ror_byte)
    return bytes(encoded_shellcode)


# Decode shellcode using ROR, ROL, SUB, ADD, and XOR
def decode_shellcode(encoded_shellcode, key):
    decoded_shellcode = bytearray()
    for i, byte in enumerate(encoded_shellcode):

        # ROR
        ror_byte = ((byte >> 7) | (byte << 1)) % 256

        # ROL
        rolled_byte = ((ror_byte >> 1) | (ror_byte << 7)) % 256

        # SUB
        subbed_byte = (rolled_byte + key[(i + 2) % len(key)]) % 256

        # ADD
        added_byte = (subbed_byte - key[(i + 1) % len(key)]) % 256

        # XOR
        xored_byte = added_byte ^ key[i % len(key)]

        decoded_shellcode.append(xored_byte)
    return bytes(decoded_shellcode)


# Generate a random key of given length and convert it into bytes
def generate_key(length):
    return bytes([random.randint(0, 255) for i in range(length)])


def info():
    print(f"""{GREEN}
                
                           _         _________   _______    _______    _          _______    _       
                          ( (    /|  \__   __/  (  ____ \  (  ____ )  ( (    /|  (  ____ \  ( (    /|
                          |  \  ( |     ) (     | (    \/  | (    )|  |  \  ( |  | (    \/  |  \  ( |
                          |   \ | |     | |     | (__      | (____)|  |   \ | |  | (__      |   \ | |
                          | (\ \) |     | |     |  __)     |     __)  | (\ \) |  |  __)     | (\ \) |
                          | | \   |     | |     | (        | (\ (     | | \   |  | (        | | \   |
                          | )  \  |  ___) (___  | (____/\  | ) \ \__  | )  \  |  | (____/\  | )  \  |
                          |/    )_)  \_______/  (_______/  |/   \__/  |/    )_)  (_______/  |/    )_)

    {RESET} {RED}                        
                                                     Author: Abhijeet Kumar
                                                  Github: github.com/wand3rlust
        
    {RESET}""")


# Menu options
def main():
    info()
    while True:
        print(f"\n"
              f"{GREEN}1. Encode shellcode\n")
        print("2. Decode shellcode\n")
        print("3. Exit\n")
        choice = input(f"Enter your choice [1-3]: {RESET}")

        if choice == "1":
            plaintext_shellcode = input("\nEnter plaintext shellcode: ")

            # Encode the user input into UTF-8 and change from string to byte
            shellcode = plaintext_shellcode.encode()

            # Generate same length key as shellcode hex
            key = generate_key(len(shellcode))

            # Call encode_shellcode function with 2 arguments i.e, UTF-8 shellcode and key
            encoded_shellcode = encode_shellcode(shellcode, key)

            print(f"\nOriginal shellcode (in hex): {RED}", shellcode.hex())
            print(f"\n{RESET}Key (in hex): {RED}", key.hex())
            print(f"\n{RESET}Encoded shellcode (in hex): {RED}", encoded_shellcode.hex())

            # Convert byte format to string
            encoded_shellcode = encoded_shellcode.hex()

            # Append \x after every 2nd character
            encoded_shellcode = "\\x" + "\\x".join(encoded_shellcode[i:i + 2]
                                                   for i in range(0, len(encoded_shellcode), 2))

            print(f"\n{RESET}Encoded shellcode (with \\x): {RED}", encoded_shellcode)
            print(f"{RESET}\n")

        elif choice == "2":
            print(f"\n{GREEN}Choose the hex format: ")
            print("\na. Normal hex")
            print("\nb. \\x format")
            choice = input(f"\nEnter your choice [a-b]: {RESET}")

            if choice == "a":

                # Convert user input hex to byte
                encoded_shellcode = bytes.fromhex(input("\nEnter encoded shellcode (in hex): "))

                # Convert user input key into byte
                key = bytes.fromhex(input("\nEnter key (in hex): "))

                # Call decode_shellcode function with 2 arguments i.e, shellcode and key
                decoded_shellcode = decode_shellcode(encoded_shellcode, key)

                # Convert encoded shellcode to hex and display
                print(f"\nEncoded shellcode (in hex): {RED}", encoded_shellcode.hex())

                # Convert key to hex and display
                print(f"\n{RESET}Key (in hex): {RED}", key.hex())

                # Convert decoded shellcode to hex and display
                print(f"\n{RESET}Decoded shellcode (in hex): {RED}", decoded_shellcode.hex())
                print("\n")

            elif choice == "b":
                encoded_shellcode = input("\nEnter encoded shellcode (with \\x): ")

                # Remove \x from hex shellcode and convert to byte
                encoded_shellcode = bytes.fromhex(encoded_shellcode.replace("\\x", ""))

                # Convert encoded shellcode to hex and display
                print(f"\nEncoded shellcode (without \\x): {RED}", encoded_shellcode.hex())

                # Convert user input key into byte
                key = bytes.fromhex(input(f"\n{RESET}Enter key (in hex): "))

                # Call decode_shellcode function with 2 arguments i.e, shellcode and key
                decoded_shellcode = decode_shellcode(encoded_shellcode, key)

                print(f"\nDecoded shellcode (in hex): {RED}", decoded_shellcode.hex())
                print(f"{RESET}\n")

            else:
                print(f"{RED}Invalid selection, start again{RESET}\n")

        elif choice == "3":
            print(f"\n{GREEN}Sayonara...{RESET}\n")
            break

        else:
            print(f"\n{RED}404: choice not found{RESET}\n")


if __name__ == "__main__":
    main()