The Hyundai vehicle was parked in Berry Lane in Wootton when the incident happened on Tuesday, October 18 at around 9.15pm.
The offenders are described as a group of six boys in their teens and two of them had bikes.
One teen was wearing a blue and red jacket, while two other boys were seen wearing one red and one white jacket.
Anyone with information can contact Northamptonshire Police on 101 or alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111.