Rear Hatch Leak....

I'm wondering if anyone else has the problem of water dripping from the rear hatch. At first, I thoght it was a sunroof thing, but I met others with no sunroof that have the same thing.

I see the water dripping from the 'shock' things that hold up the trunk, but I can't see where its coming from, or how to fix it. Is this a common problem, and how do I stop it??