init

shellcoder.py

@@ -0,0 +1,102 @@
+#!/usr/bin/env python3
+#
+# Shellcoder.py : 
+#
+# Author: Print3M (https://github.com/Print3M)
+# 
+# This script helps automate the shellcode testing process.
+# It takes an Assembly file with shellcode, compiles
+# it into machine code (NASM), generates a payload in C with that,
+# and pastes it into the loader C file. Finally, the prepared C file
+# is compiled using MSVC. With this script you go from Assembly
+# shellcode to executable file with one command! 
+#   
+# External dependencies:
+#   - Python 3
+#   - NASM (Netwide Assembler)
+#   - Visual Studio 2022
+
+import subprocess
+import os
+import sys
+
+# Directory with output files
+OUT_DIR = "out"
+
+# Utility files
+SHELLCODE_INPUT_FILE = "shellcode.asm"
+SHELLCODE_OUTPUT_FILE = f"{OUT_DIR}\\shellcode.bin"
+LOADER_INPUT_FILE = "loader.c"
+LOADER_OUTPUT_FILE = f"{OUT_DIR}\\malware.c"
+
+# String to be replaced by generated payload
+PAYLOAD_STRING = ":PAYLOAD:"
+
+# Name of final binary output file
+BINARY_OUTPUT_FILE = f"{OUT_DIR}\\malware.exe"
+
+# Batch script with Visual Studio compiler environment variables
+MSVC_BATCH_SCRIPT = "C:\\Program Files\\Microsoft Visual Studio\\2022\\Community\\VC\\Auxiliary\\Build\\vcvars64.bat"
+
+
+def is_cmd_available(cmd: str):
+    try:
+        subprocess.call(cmd, text=True)
+    except FileNotFoundError:
+        return False
+    
+    return True
+
+
+def assert_cmd(cmd: str):
+    if (is_cmd_available(cmd)):
+        return 
+
+    print(f"[!] command not found: {cmd}", file=sys.stderr)    
+    sys.exit(-1)
+
+
+if __name__ == "__main__":
+    # Check if NASM is available
+    assert_cmd("nasm")
+
+    # Prepare output directory
+    os.makedirs(OUT_DIR, exist_ok=True)
+
+    # Compile Assembly
+    subprocess.run(
+        ["nasm", "-f", "win64", SHELLCODE_INPUT_FILE, "-o", SHELLCODE_OUTPUT_FILE], check=True
+    )
+
+    print(f"[+] NASM: {SHELLCODE_INPUT_FILE} -> {SHELLCODE_OUTPUT_FILE}")
+
+    # Prepare C array with shellcode payload
+    payload = ""
+    with open(SHELLCODE_OUTPUT_FILE, "rb") as f:
+        bytes = bytearray(f.read())
+
+    size = len(bytes)
+
+    for byte in bytes:
+        payload += "\\" + hex(byte).lstrip("0")
+
+    print(f"[+] Payload size: {size} bytes")
+
+    # Inject payload into loader source code
+    with open(LOADER_INPUT_FILE, "r") as f:
+        loader = f.read()
+
+    loader = loader.replace(PAYLOAD_STRING, payload)
+
+    with open(LOADER_OUTPUT_FILE, "w") as f:
+        f.write(loader)
+
+    print(f"[+] {LOADER_INPUT_FILE} -> {LOADER_OUTPUT_FILE}")
+
+    # Compile final binary
+    print(f"[*] MSVC: Compilation of {LOADER_OUTPUT_FILE} \n")
+
+    cmd = f'"{MSVC_BATCH_SCRIPT}" && cd "{OUT_DIR}" && cl.exe "../{LOADER_OUTPUT_FILE}"'
+    proc = subprocess.run(cmd, check=True, text=True)
+
+    print(f"\n[+] Output binary ({BINARY_OUTPUT_FILE}) is ready to be executed!")