Add shellcode encoder for raw binary (.bin) files

Linux Shellcode Encoder/shellcodeCrypter-bin.py

@@ -0,0 +1,86 @@
+#!/usr/bin/python3
+
+# Basic shellcode crypter for C# payloads
+# By Cas van Cooten
+
+import re
+import platform
+import argparse
+import subprocess
+from random import randint
+
+if platform.system() != "Linux":
+    exit("[x] ERROR: Only Linux is supported for this utility script.")
+
+class bcolors:
+    OKBLUE = '\033[94m'
+    OKGREEN = '\033[92m'
+    FAIL = '\033[91m'
+    ENDC = '\033[0m'
+    BOLD = '\033[1m'
+
+# Parse input arguments
+def auto_int(x):
+    return int(x, 0)
+
+parser = argparse.ArgumentParser()
+parser.add_argument("path", help="the path to load the raw shellcode payload from", nargs='?', default="/tmp/payload.bin")
+parser.add_argument("type", help="the encoding type to use ('xor' or 'rot')", nargs='?', default="xor")
+parser.add_argument("key", help="the key to encode the payload with (integer)", type=auto_int, nargs='?', default=randint(1,255))
+args = parser.parse_args()
+
+# Generate the shellcode given the input path
+print(f"{bcolors.BOLD}{bcolors.OKBLUE}[i] Generating payload for path {bcolors.OKGREEN}{args.path}{bcolors.ENDC}.")
+try:
+    with open(args.path, "rb") as f:
+        payload = f.read()
+
+except:
+    print(f'{bcolors.BOLD}{bcolors.FAIL}[-] Cannot read file:', args.path)  
+    exit(1)
+
+# Encode the payload with the chosen type and key
+print(f"{bcolors.BOLD}{bcolors.OKBLUE}[i] Encoding payload with type {bcolors.OKGREEN}{args.type}{bcolors.OKBLUE} and key {bcolors.OKGREEN}{hex(args.key)}{bcolors.ENDC}")
+encodedPayload = []
+payloadFormatted = ""
+for byte in payload:
+    byteInt = int(byte)
+
+    if args.type == "xor":
+        byteInt = byteInt ^ args.key
+    elif args.type == "rot":
+        byteInt = byteInt + args.key & 255
+    else:
+        exit(f"{bcolors.BOLD}{bcolors.FAIL}[x] ERROR: Invalid encoding type.{bcolors.ENDC}")
+
+    encodedPayload.append("{0:#0{1}x}".format(byteInt,4))
+
+# Format the output payload
+payLen = len(encodedPayload)
+encodedPayload = re.sub("(.{65})", "\\1\n", ','.join(encodedPayload), 0, re.DOTALL)
+payloadFormatted += f"// Payload {args.type}-encoded with key {hex(args.key)}\n"
+payloadFormatted += f"byte[] buf = new byte[{str(payLen)}] {{\n{encodedPayload}\n}};"
+if payLen > 1000:
+    f = open("/tmp/payload.txt", "w")
+    f.write(payloadFormatted)
+    f.close()
+    print(f"{bcolors.BOLD}{bcolors.OKGREEN}[+]{bcolors.OKBLUE} Encoded payload written to {bcolors.OKGREEN}/tmp/payload.txt{bcolors.OKBLUE} in CSharp format!{bcolors.ENDC}")
+else:
+    print(f"{bcolors.BOLD}{bcolors.OKGREEN}[+]{bcolors.OKBLUE} Encoded payload (CSharp):{bcolors.ENDC}")
+    print(payloadFormatted + "\n")
+
+# Provide the decoding function for the heck of it
+print(f"{bcolors.BOLD}{bcolors.OKBLUE}[i] Decoding function:{bcolors.ENDC}")
+if args.type == "xor":
+    decodingFunc = f"""for (int i = 0; i < buf.Length; i++)
+{{
+    buf[i] = (byte)((uint)buf[i] ^ {hex(args.key)});
+}}"""
+
+if args.type == "rot":
+    decodingFunc = f"""for (int i = 0; i < buf.Length; i++)
+{{
+    buf[i] = (byte)(((uint)buf[i] - {hex(args.key)}) & 0xFF);
+}}"""
+
+print(decodingFunc)