第一个PUSH EBP指令是void * f(int32_t n)的开始(idk它返回的内容,只是猜测void *),我知道输入参数n在堆栈中,而EBP 8是指向它的指针变量,我想它会是这样的
int * n =(int *)(uint32_t(EBP)0x08); / *假设EBP是void *和sizeof(EBP)== sizeof(uint32_t)== sizeof(void *),并且8数学在c uint32_t和x86程序集中是相同的.* /
我想制作一个钩子,它将检查n是否高于7或低于0,如果是,则将其更改为1.使用ollydbg,直接编写汇编代码,我可以这样做:
修补第一个MOV EBP,ESP指令到JMP SHORT到它后面的INT3指令(我需要7个字节),然后将(未使用的)INT3改为
MOV EBP,ESP
JMP LONG 0068BCCD
其中0068BCCD是文件末尾未使用的0x000000000000
,然后在0068BCCD,我可以编写汇编代码来检查EBP 8指向的int,并在必要时修改它:
PUSHAD CMP DWORD PTR SS:[EBP+8],7 JA SHORT Error CMP DWORD PTR SS:[EBP+8],0 JL SHORT Error JMP SHORT Finished Error: PUSHAD PUSH OFFSET TheString CALL Onlink-x86.App::Output ADD ESP,4 POPAD MOV DWORD PTR SS:[EBP+8],1 Finished: POPAD JMP LONG 00447493 TheString: "Warning: label assertion Failed,but (pretending its 1 and) trying to ignore.."+0x00
哪个(如果我没有搞砸)基本上相当于
void FilterIntAtEBP_8(){ int i=*(int*)(uint32_t(EBP)+8); if(i>7 || i<0){ Output("Warning: label assertion Failed,but (pretending its 1 and) trying to ignore.."); *(int*)(uint32_t(EBP)+8)=1; } return; }
最后,问题是:如何使用Ollydbg,而不是使用C? (我看到了一个源代码回来,一个MMORPG作弊程序,挂钩客户端,执行此操作,但代码丢失给我)
Injector.h
#ifndef INJECTOR_H_INCLUDED #define INJECTOR_H_INCLUDED #include <Windows.h> #include <string> class Injector { public: /** * Loads a DLL into the remote process * @Return true on sucess,false on failure */ bool InjectDll(DWORD processId,std::string dllPath); private: }; #endif // INJECTOR_H_INCLUDED
Injector.cpp
#include "Injector.h" bool Injector::InjectDll(DWORD processId,std::string dllPath) { HANDLE hThread,hProcess; void* pLibRemote = 0; // the address (in the remote process) where szLibPath will be copied to; HMODULE hKernel32 = GetModuleHandle("Kernel32"); HINSTANCE hInst = GetModuleHandle(NULL); char DllFullPathName[_MAX_PATH]; GetFullPathName(dllPath.c_str(),_MAX_PATH,DllFullPathName,NULL); // Get process handle hProcess = OpenProcess(PROCESS_ALL_ACCESS,FALSE,processId); // copy file path in szLibPath char szLibPath[_MAX_PATH]; strcpy_s(szLibPath,DllFullPathName); // 1. Allocate memory in the remote process for szLibPath pLibRemote = VirtualAllocEx( hProcess,NULL,sizeof(szLibPath),MEM_COMMIT,PAGE_READWRITE ); if (pLibRemote == NULL) { // probably because you don't have administrator's right return false; } // 2. Write szLibPath to the allocated memory WriteProcessMemory(hProcess,pLibRemote,(void*)szLibPath,NULL); // 3. Force remote process to load dll hThread = CreateRemoteThread(hProcess,(LPTHREAD_START_ROUTINE) GetProcAddress(hKernel32,"LoadLibraryA"),NULL); if (hThread == NULL) { return false; } return true; }
main.cpp中
#include "Injector.h" int main() { Injector injector; DWORD processId = 1653; // change the process id here. if (injector.InjectDll(processId,"injected.dll")) { printf("Good job,you injected the dll\n"); } else { printf("Something wrong happened\n"); } while (true); }
然后你必须做你的DLL.这是它变得更复杂的地方.首先一些包括:
injected.dll
#include <Windows.h> #include <stdio.h>
然后我们需要创建一个绕过正确位置的函数:
void DetourAddress(void* funcPtr,void* hook,BYTE* mem) { BYTE cmd[5] = { 0xE9,0x00,0x00 }; // jump place holder void* RVAaddr = (void*)((DWORD)funcPtr + (DWORD)GetModuleHandle(NULL)); // base + relative address // make memory readable/writable DWORD dwProtect; VirtualProtect(RVAaddr,5,PAGE_EXECUTE_READWRITE,&dwProtect); // read memory ReadProcessMemory(GetCurrentProcess(),(LPVOID)RVAaddr,&mem[2],NULL); // write jmp in cmd DWORD offset = ((DWORD)hook - (DWORD)RVAaddr - 5); // (dest address) - (source address) - (jmp size) memcpy(&cmd[1],&offset,4); // write address into jmp WriteProcessMemory(GetCurrentProcess(),cmd,0); // write jmp // write mem VirtualProtect(mem,13,&dwProtect); void* returnAdress = (void*)((DWORD)RVAaddr + 5); memcpy(&mem[8],&returnAdress,4); // write return address into mem // reprotect VirtualProtect(RVAaddr,dwProtect,NULL); }
void PatchAddress(void* funcPtr,BYTE* mem) { void* RVAaddr = (void*)((DWORD)funcPtr + (DWORD)GetModuleHandle(NULL)); // base + relative address // make memory readable/writable DWORD dwProtect; VirtualProtect(funcPtr,&dwProtect); WriteProcessMemory(GetCurrentProcess(),NULL); // write jmp VirtualProtect(RVAaddr,NULL); }
接下来,我们需要从绕行的字节中创建一个函数,以便程序执行它们,这样它就不会受到绕行的影响.在全球空间中添加:
// memory (0x5E = pop esi,0x68 = push DWORD,0xC3 = RETN) BYTE detourMem[13] = { 0x5E,0x5E,0x0,0x68,0xC3 }; // Convert bytes array to function typedef void ( * pFunc)(); pFunc funcMem = (pFunc) &detourMem; // I also added a variable as an example of what you can do with it. DWORD var = 0;
之后,您需要绕行功能:
_declspec(naked) void DetourFunction() { // we need to push all flag and registers on the stack so we don't modify them by accident __asm { PUSHFD PUSHAD // You can do "whatever" you want here in assembly code // ex,put eax value into var: mov var,eax } printf("this code is executed everytime the detoured function is called\n"); // Do whatever you want in c++ here if (var < 7) { // eax was smaller than 7 } // We pop every flags and registers we first pushed so that the program continue as it was supposed to __asm { // we set everything back to normal POPAD POPFD push esi // we call our funcMem mov edx,funcMem; call edx } }
最后,这是你的DLLMain的样子:
BOOL APIENTRY DllMain( HMODULE hModule,DWORD ul_reason_for_call,LPVOID lpReserved ) { DWORD detouredAddress = 0x689B; // add the RELATIVE ADDRESS of the location you want to detour FILE *stream; switch (ul_reason_for_call) { case DLL_PROCESS_ATTACH: // Only add this if you want a console to appears when you inject your dll (don't forget FreeConsole when you remove the dll) AllocConsole(); freopen_s(&stream,"CONOUT$","w",stdout); // If you need to know the base address of the process your injected: printf("base address: 0x%X\n",(DWORD)GetModuleHandle(NULL)); // Our detour function DetourAddress((void*)detouredAddress,(void*)&DetourFunction,detourMem); break; case DLL_PROCESS_DETACH: // We restore the process to have what it was before it was injected PatchAddress((void*)detouredAddress,detourMem); FreeConsole(); break; } return true; }
我明白这一切都很多,所以如果你有任何问题请不要犹豫!