Both contain protein. The amount varies by the type for cheese, although it appears to be about 20% - 35%. All dairy contains protein. There may also be milk or cream in the sauce, which would also be a contributing ingredient.
Pasta also contains protein, but less than cheese. The amount depends on the type of flour used. It will also increase if egg is used in the pasta. If you look at Barilla, their normal penne has about 7g of protein in a 56g serving, or 12.5%.
Looking at the ingredients, there appears to be a couple of different types of cheese in the pasta as well as milk and cream. They would all contribute protein.
Beef is about 29% protein. So dairy is on par or better than meat as a protein source, but pasta falls well short of it.