const
  //Target: array [0 .. 7] of Byte = ($59, $6F, $75, $72, $20, $49, $44, $3A);
  DefaultBufSize = 4 * 1024;

begin
  A := 'Your ID: %s';
  B := BytesOf(A);
  FillChar(Mbi, SizeOf(Mbi), #0);
  FillChar(Addr, SizeOf(Addr), #0);
  AppSize := 0;

  BuffSize := 1024 * 4 + SizeOf(B);
  ProcID := GetProcessIDExt('App.exe');
  Handle := OpenProcess(PROCESS_ALL_ACCESS, FALSE, ProcID);
  if ProcID > 0 then
  begin
    Addr := Cardinal(GetModuleBaseAddress(ProcID, 'App.exe'));
    AppSize := GetModuleSize(ProcID, 'App.exe');
    Memo1.Lines.Add(inttostr(AppSize));
    MaxAddr := Addr + AppSize;
    Memo1.Lines.Add(format('%p', [ptr(Addr)]));
    Memo1.Lines.Add(format('%p', [ptr(MaxAddr)]));

    while Addr < MaxAddr do
    begin
      if VirtualQueryEx(Handle, ptr(Addr), Mbi, SizeOf(Mbi)) <> 0 then
      begin
        SetLength(buff, BuffSize);
        if ReadProcessMemory(Handle, Mbi.BaseAddress, @buff, Mbi.RegionSize,
          BytesRead) then
        begin
          if BytePos(B, @buff, SizeOf(buff)) <> nil then
          begin
            ShowMessage('Found');
            Memo1.Lines.Add(inttohex(Addr));
          end;
        end;
        if Addr + BuffSize < Addr then
          break;

        Addr := Addr + DefaultBufSize;
        Memo1.Lines.Add(format('%p', [ptr(Addr)]));
      end;
      SetLength(buff, 0);
    end;
  end;

function BytePos(const Pattern: TBytes; const Buffer: PByte;
  const BufLen: Cardinal): PByte;
var
  PatternLength: Cardinal;
  i: Cardinal;
  j: Cardinal;
  OK: boolean;
begin
  Result := nil;
  PatternLength := Length(Pattern);
  if PatternLength > BufLen then
    Exit;
  if PatternLength = 0 then
    Exit(Buffer);
  for i := 0 to BufLen - PatternLength do
    if PByte(Buffer + i)^ = Pattern[0] then
    begin
      OK := true;
      for j := 1 to PatternLength - 1 do
        if PByte(Buffer + i + j)^ <> Pattern[j] then
        begin
          OK := FALSE;
          break
        end;
      if OK then
        Exit(Buffer + i);
    end;
end;