Well, there are a few ways to explain this away. The easiest of which is to say it is not in a single key. The first chord is minor, suggesting a minor key. But aeolian and dorian are the most common minor keys and their respective VII chords are major, and the second chord here is minor.

This gives us a second option. The third minor key, phrygian, has a minor VII chord, and since there are only two chords here each containing the root and the third, we can say that it is in C phrygian. It depends on what the rest of the song is.

Remember that analyzing music isn't always so cut and dry. There are usually a few answers for every situation.