No, one of the first things that is considered when deciding if an unknown missile is hostile is to look at its point of origin (comically abbreviated POO). If

No, one of the first things that is considered when deciding if an unknown missile is hostile is to look at its point of origin (comically abbreviated POO). If a missile originates from NK, then Russia would first assume it is headed for the US. They would need to gather trajectory information indicating that the missile was heading for a Russian target before they did anything. They would be pissed at North Korea for starting WWIII, but would probably just let the missile fly overhead and try to take advantage of the political situation later.