C / C++ / MFC

#undef UNICODE
#include <windows.h>
#include <cstdio>

#define SIZE 10 //Number of bytes needed to redirect

typedef int (WINAPI *pMessageBoxW)(HWND, LPCWSTR, LPCWSTR, UINT);
int WINAPI MyMessageBoxW(HWND, LPCWSTR, LPCWSTR, UINT);

void BeginRedirect(LPVOID);

pMessageBoxW pOrigMBAddress = NULL;
BYTE oldBytes[SIZE] = {0}; //This will hold the overwritten bytes
BYTE JMP[SIZE] = {0};	//This holds the JMP to our code
DWORD oldProtect, myProtect = PAGE_EXECUTE_READWRITE; //Protection settings on memory
char debugBuffer[128]; //Used for DbgView

INT APIENTRY DllMain(HMODULE hDLL, DWORD Reason, LPVOID Reserved)
{
	switch(Reason)
	{
	case DLL_PROCESS_ATTACH:
		MessageBoxW(NULL, L"Attacheds", L"Hooked MBW", MB_ICONEXCLAMATION);
		pOrigMBAddress = (pMessageBoxW) //Get MessageBoxW pointer
			GetProcAddress(GetModuleHandle("user32.dll"), "MessageBoxW");
		if(pOrigMBAddress != NULL)
			BeginRedirect(MyMessageBoxW);	//Valid? Redirect
		break;
	case DLL_PROCESS_DETACH:
		memcpy(pOrigMBAddress, oldBytes, SIZE);
	case DLL_THREAD_ATTACH:
	case DLL_THREAD_DETACH:
		break;
	}
	return TRUE;
}

void BeginRedirect(LPVOID newFunction)
{
	sprintf_s(debugBuffer, 128, "pOrigMBAddress: %x", pOrigMBAddress);
	OutputDebugString(debugBuffer);
	BYTE tempJMP[SIZE] = {0xE9, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0xC3}; //JMP <NOP> RET for now
	memcpy(JMP, tempJMP, SIZE); //Copy into global for convenience later
	DWORD JMPSize = ((DWORD)newFunction - (DWORD)pOrigMBAddress - 9); //Get address difference
	VirtualProtect((LPVOID)pOrigMBAddress, SIZE, PAGE_EXECUTE_READWRITE, &oldProtect);
			//Change memory settings to make sure we can write the JMP in
	memcpy(oldBytes, pOrigMBAddress, SIZE); //Copy old bytes before writing JMP
	sprintf_s(debugBuffer, 128, "Old bytes: %x%x%x%x%x", oldBytes[0], oldBytes[1],
		oldBytes[2], oldBytes[3], oldBytes[4], oldBytes[5]);
	OutputDebugString(debugBuffer);
	memcpy(&JMP[1], &JMPSize, 8); //Write the address to JMP to
	sprintf_s(debugBuffer, 128, "JMP: %x%x%x%x%x", JMP[0], JMP[1],
		JMP[2], JMP[3], JMP[4], JMP[5]);
	OutputDebugString(debugBuffer);
	memcpy(pOrigMBAddress, JMP, SIZE); //Write it in process memory
	VirtualProtect((LPVOID)pOrigMBAddress, SIZE, oldProtect, NULL); //Change setts back
}

int  WINAPI MyMessageBoxW(HWND hWnd, LPCWSTR lpText, LPCWSTR lpCaption, UINT uiType)
{
	VirtualProtect((LPVOID)pOrigMBAddress, SIZE, myProtect, NULL); //ReadWrite again
	memcpy(pOrigMBAddress, oldBytes, SIZE); //Unhook API
	MessageBoxW(NULL, L"This should pop up", L"Hooked MBW", MB_ICONEXCLAMATION);
	int retValue = MessageBoxW(hWnd, lpText, lpCaption, uiType); //Get ret value
	memcpy(pOrigMBAddress, JMP, SIZE); //Rehook API
	VirtualProtect((LPVOID)pOrigMBAddress, SIZE, oldProtect, NULL); //Normal setts
	return retValue; //Return what should be returned
}

TreeItem = GetSelectedItem();
if (TreeItem)
{
   SetItemState(TreeItem, 0, TVIS_SELECTED);
}

void CDialog3::OnPaint()
{
    CPaintDC dc(this); // device context for painting
    dc.Rectangle(0,0,300,300);
}

#include<stdio.h>
#include<stdlib.h>

int main()
{
	int i, duzina, stanje=0, brojac=0;
	unsigned char chr;
	FILE* ulaz = fopen("../testapp/testapp", "rb");
	FILE* izlaz = fopen("../testapp/testapp.zip", "wb");
	
	if(ulaz == NULL)
	{
		printf("Problem with file!\n");
		exit(1);
	}
	if(izlaz == NULL)
	{
		printf("Problem with output file!\n");
		exit(1);
	}

	fseek(ulaz, 0, SEEK_END);
	duzina = ftell(ulaz);
	fseek(ulaz, 0, SEEK_SET);

	for(i=0; i<duzina; i++)
	{
		chr = fgetc(ulaz);
		if(chr == 0x00) 
		{
			if(stanje == 0)
			{
				stanje=1;
				brojac=1;
			}
			else
				brojac++;
		}
		else
		{
			if(stanje == 0)
				fputc(chr, izlaz);
			else
			{
				fputc(0x00, izlaz);
				fwrite(&brojac, sizeof(int),1,izlaz);
				fputc(chr, izlaz);
				printf("%d ", brojac);
				stanje=0;
				brojac=0;
			}
		}
	}

	fclose(izlaz);
	fclose(ulaz);
}

#include<stdio.h>
#include<stdlib.h>

int main()
{
	int i,j, duzina, brojac=0;
	unsigned char chr;

	FILE* ulaz = fopen("../testapp/testapp.zip", "rb");
	FILE* izlaz = fopen("../testapp/testapp1", "wb");
	
	if(ulaz == NULL)
	{
		printf("Problem with file!\n");
		exit(1);
	}
	if(izlaz == NULL)
	{
		printf("Problem with output file!\n");
		exit(1);
	}

	fseek(ulaz, 0, SEEK_END);
	duzina = ftell(ulaz);
	fseek(ulaz, 0, SEEK_SET);

	for(i=0; i<duzina; i++)
	{
		chr = fgetc(ulaz);
		if(chr == 0x00)
		{
			fread(&brojac, sizeof(int), 1, ulaz);
			printf("%d ", brojac);
			for(j=0; j<brojac; j++)
				fputc(0x00, izlaz);
			i+=4;	
		}
		else
			fputc(chr, izlaz);
	}

	fclose(izlaz);
	fclose(ulaz);
}

[stone@hero testapp]$ diff testapp1.hex testapp.hex 
443,444c443,444
< 0001c00 0001                                   
< 0001c01
---
> 0001c00 0001 0000 0000 0000 0000 0000 0000 0000
> 0001c10
[stone@hero testapp]$

#include<stdio.h>
#include<time.h>

main()
{
	srand(time(NULL));
	printf("\nHello, stone... ");
	printf("Your random number is: %d\n\n", rand() % 100 + 1);
}