之前说了怎么写机器码到内存,然后调用。现在说说怎么优化。
用Python发送微信消息给好友
再看一遍c语言的代码
void SendText( wchar_t* wsTextMsg) {
// 发送的好友,filehelper是文件传输助手
wchar_t wsWxId[0x10] = L"filehelper";
WxBaseStruct wxWxid(wsWxId);
// 发送的消息内容
WxBaseStruct wxTextMsg(wsTextMsg);
wchar_t** pWxmsg = &wxTextMsg.buffer;
char buffer[0x3B0] = { 0 };
char wxNull[0x100] = { 0 };
DWORD dllBaseAddress = (DWORD)GetModuleHandleA("WeChatWin.dll");
// 发消息的函数call地址
DWORD callAddress = dllBaseAddress + 0x521D30;
__asm {
lea eax, wxNull;
push 0x1;
push eax;
mov edi, pWxmsg;
push edi;
lea edx, wxWxid;
lea ecx, buffer;
call callAddress;
add esp, 0xC;
}
}
上面的代码真正发消息的是asm里面的代码,之前的c代码都是在组装内存数据。那我们是不是可以用Python组装数据,只讲下面的汇编转为机器码写入内存调用,这样就少了很多无用的机器码。
改完的SendText函数如下
wchar_t wsWxId[0x10] = L"filehelper";
wchar_t wsTextMsg[0x100] = L"test";
WxBaseStruct wxWxid(wsWxId);
WxBaseStruct wxTextMsg(wsTextMsg);
wchar_t** pWxmsg = &wxTextMsg.buffer;
char buffer[0x3B0] = { 0 };
char wxNull[0x100] = { 0 };
DWORD dllBaseAddress = (DWORD)GetModuleHandleA("WeChatWin.dll");;
DWORD callAddress = dllBaseAddress + 0x521D30;
void SendText() {
__asm {
lea eax, wxNull;
push 0x1;
push eax;
mov edi, pWxmsg;
push edi;
lea edx, wxWxid;
lea ecx, buffer;
call callAddress;
add esp, 0xC;
}
}
汇编代码:
[]里面包含的类型和变量名其实就是地址,只需要将地址改成用Python构造的地址就可以了
完整代码如下:
import os
import pymem
import ctypes
import time
def convert_addr(addr):
if isinstance(addr, int):
addr = hex(addr)
if addr.startswith("0x") or addr.startswith("0X"):
addr = addr[2:]
if len(addr) < 8:
addr = (8-len(addr))*'0' + addr
tmp = []
for i in range(0, 8, 2):
tmp.append(addr[i:i+2])
tmp.reverse()
return ''.join(tmp)
def WxBaseStruct(process_handle, content):
struct_address = pymem.memory.allocate_memory(process_handle, 20)
bcontent = content.encode('utf-16le')
content_address = pymem.memory.allocate_memory(process_handle, len(bcontent)+16)
pymem.ressources.kernel32.WriteProcessMemory(process_handle, content_address, bcontent, len(bcontent), None)
pymem.memory.write_int(process_handle, struct_address, content_address)
pymem.memory.write_int(process_handle, struct_address+0x4, len(content))
pymem.memory.write_int(process_handle, struct_address+0x8, len(content)*2)
pymem.memory.write_int(process_handle, struct_address+0xC, 0)
pymem.memory.write_int(process_handle, struct_address+0x10, 0)
return struct_address, content_address
def start_thread(process_handle, address, params=None):
params = params or 0
NULL_SECURITY_ATTRIBUTES = ctypes.cast(0, pymem.ressources.structure.LPSECURITY_ATTRIBUTES)
thread_h = pymem.ressources.kernel32.CreateRemoteThread(
process_handle,
NULL_SECURITY_ATTRIBUTES,
0,
address,
params,
0,
ctypes.byref(ctypes.c_ulong(0))
)
last_error = ctypes.windll.kernel32.GetLastError()
if last_error:
pymem.logger.warning('Got an error in start thread, code: %s' % last_error)
pymem.ressources.kernel32.WaitForSingleObject(thread_h, -1)
return thread_h
def main(wxpid, wxid, msg):
process_handle = pymem.process.open(wxpid)
wxNull_address = pymem.memory.allocate_memory(process_handle, 0x100)
buffer_address = pymem.memory.allocate_memory(process_handle, 0x3B0)
wxid_struct_address, wxid_address = WxBaseStruct(process_handle, wxid)
msg_struct_address, msg_address = WxBaseStruct(process_handle, msg)
process_WeChatWin_handle = pymem.process.module_from_name(process_handle, "WeChatWin.dll")
call_address = process_WeChatWin_handle.lpBaseOfDll + 0x521D30
call_p_address = pymem.memory.allocate_memory(process_handle, 4)
pymem.memory.write_int(process_handle, call_p_address, call_address)
format_code = '''
57
8D05 {wxNull}
6A 01
50
8D3D {wxTextMsg}
57
8D15 {wxWxid}
8D0D {buffer}
FF15 {callAddress}
83C4 0C
5F
C3
'''
shellcode = format_code.format(wxNull=convert_addr(wxNull_address),
wxTextMsg=convert_addr(msg_struct_address),
wxWxid=convert_addr(wxid_struct_address),
buffer=convert_addr(buffer_address),
callAddress=convert_addr(call_p_address))
shellcode = bytes.fromhex(shellcode.replace(' ', '').replace('\n', ''))
shellcode_address = pymem.memory.allocate_memory(process_handle, len(shellcode)+5)
pymem.ressources.kernel32.WriteProcessMemory(process_handle, shellcode_address, shellcode, len(shellcode), None)
thread_h = start_thread(process_handle, shellcode_address)
time.sleep(0.5)
pymem.memory.free_memory(process_handle, wxNull_address)
pymem.memory.free_memory(process_handle, buffer_address)
pymem.memory.free_memory(process_handle, wxid_struct_address)
pymem.memory.free_memory(process_handle, wxid_address)
pymem.memory.free_memory(process_handle, msg_struct_address)
pymem.memory.free_memory(process_handle, msg_address)
pymem.memory.free_memory(process_handle, call_p_address)
pymem.memory.free_memory(process_handle, shellcode_address)
pymem.process.close_handle(process_handle)
if __name__ == "__main__":
wxpid = 16892
wxid = "filehelper"
msg = "python test"
main(wxpid, wxid, msg)
直接在Python里写汇编,然后自动转机器码写入内存。使用的是Python的keystone库
# -*- coding: utf-8 -*-
import os
import pymem
import ctypes
import time
from keystone import Ks, KS_ARCH_X86, KS_MODE_32
def asm2code(asm_code, syntax=0):
ks = Ks(KS_ARCH_X86, KS_MODE_32)
bytes_code, _ = ks.asm(asm_code, as_bytes=True)
return bytes_code
def WxBaseStruct(process_handle, content):
struct_address = pymem.memory.allocate_memory(process_handle, 20)
bcontent = content.encode('utf-16le')
content_address = pymem.memory.allocate_memory(process_handle, len(bcontent)+16)
pymem.ressources.kernel32.WriteProcessMemory(process_handle, content_address, bcontent, len(bcontent), None)
pymem.memory.write_int(process_handle, struct_address, content_address)
pymem.memory.write_int(process_handle, struct_address+0x4, len(content))
pymem.memory.write_int(process_handle, struct_address+0x8, len(content)*2)
pymem.memory.write_int(process_handle, struct_address+0xC, 0)
pymem.memory.write_int(process_handle, struct_address+0x10, 0)
return struct_address, content_address
def start_thread(process_handle, address, params=None):
params = params or 0
NULL_SECURITY_ATTRIBUTES = ctypes.cast(0, pymem.ressources.structure.LPSECURITY_ATTRIBUTES)
thread_h = pymem.ressources.kernel32.CreateRemoteThread(
process_handle,
NULL_SECURITY_ATTRIBUTES,
0,
address,
params,
0,
ctypes.byref(ctypes.c_ulong(0))
)
last_error = ctypes.windll.kernel32.GetLastError()
if last_error:
pymem.logger.warning('Got an error in start thread, code: %s' % last_error)
pymem.ressources.kernel32.WaitForSingleObject(thread_h, -1)
return thread_h
def main(wxpid, wxid, msg):
process_handle = pymem.process.open(wxpid)
wxNull_address = pymem.memory.allocate_memory(process_handle, 0x100)
buffer_address = pymem.memory.allocate_memory(process_handle, 0x3B0)
wxid_struct_address, wxid_address = WxBaseStruct(process_handle, wxid)
msg_struct_address, msg_address = WxBaseStruct(process_handle, msg)
process_WeChatWin_handle = pymem.process.module_from_name(process_handle, "WeChatWin.dll")
call_address = process_WeChatWin_handle.lpBaseOfDll + 0x521D30
call_p_address = pymem.memory.allocate_memory(process_handle, 4)
pymem.memory.write_int(process_handle, call_p_address, call_address)
format_asm_code = '''
push edi;
lea eax,dword ptr ds:[{wxNull:#02x}];
push 0x1;
push eax;
lea edi,dword ptr ds:[{wxTextMsg:#02x}];
push edi;
lea edx,dword ptr ds:[{wxWxid:#02x}];
lea ecx,dword ptr ds:[{buffer:#02x}];
call dword ptr ds:[{callAddress:#02x}];
add esp, 0xC;
pop edi;
ret;
'''
asm_code = format_asm_code.format(wxNull=wxNull_address,
wxTextMsg=msg_struct_address,
wxWxid=wxid_struct_address,
buffer=buffer_address,
callAddress=call_p_address)
shellcode = asm2code(asm_code.encode())
shellcode_address = pymem.memory.allocate_memory(process_handle, len(shellcode)+5)
pymem.ressources.kernel32.WriteProcessMemory(process_handle, shellcode_address, shellcode, len(shellcode), None)
thread_h = start_thread(process_handle, shellcode_address)
time.sleep(0.5)
pymem.memory.free_memory(process_handle, wxNull_address)
pymem.memory.free_memory(process_handle, buffer_address)
pymem.memory.free_memory(process_handle, wxid_struct_address)
pymem.memory.free_memory(process_handle, wxid_address)
pymem.memory.free_memory(process_handle, msg_struct_address)
pymem.memory.free_memory(process_handle, msg_address)
pymem.memory.free_memory(process_handle, call_p_address)
pymem.memory.free_memory(process_handle, shellcode_address)
pymem.process.close_handle(process_handle)
if __name__ == "__main__":
wxpid = 18604
wxid = "filehelper"
msg = "python test msg"
main(wxpid, wxid, msg)