A crash box includes a body portion extending from a top edge to a bottom edge along a global z-axis (A) and having a pair of side walls disposed in spaced relationship to one another. At least one x-shaped reinforcing web extends between the side walls along a plane (P) disposed transverse to the axis (A). An extension portion is integral with the body portion and extends outwardly from one of the side walls and is disposed along the plane (P). A flange plate is also integral with the body portion and defines at least one flange plate attachment hole for securing the crash box to a frame of a vehicle.