GILZE-RIJEN AIR BASE, Netherlands—Investigators probing the downing of Malaysia Airlines Flight 17 concluded that a sophisticated, Russia-made antiaircraft missile struck the Boeing 777 jetliner, causing it to break apart in midair before the wreckage plummeted for up to a minute and a half to the ground.

The Buk missile was fired from eastern Ukraine, said Tjibbe Joustra, chairman of the Dutch Safety Board, which on Tuesday published its final report into the 2014 crash that killed all 298 people on board.

The...