digraph G {
  node [ shape = "circle" ];
  {
    rank = same;
    b1 [ label = "1" ];
    b2 [ label = "2" ];
    b3 [ label = "3" ];
  }
  cc -> b1 [ dir = "back" ];
  cc -> b2 [ dir = "back" ];
  cc -> b3 [ dir = "back" ];
  {
    rank = same;
    cc [ label = "C2 server"; shape = "box" ];
    b4 [ label = "4" ];
    b5 [ label = "5" ];
    cc -> b4 [ dir = "back" ];
    cc -> b5 [ dir = "back" ];
  }
  {
    rank = same;
    b6 [ label = "6" ];
    b7 [ label = "7" ];
    b8 [ label = "8" ];
    b9 [ label = "9" ];
  }
  cc -> b6 [ dir = "back" ];
  cc -> b7 [ dir = "back" ];
  cc -> b8 [ dir = "back" ];
  cc -> b9 [ dir = "back" ];
}