Oil Leak from spark plugs

[redeye280z]

I have a 2000 Boxster S I recently did my oil change and while I was under the car I noticed oil seeping from the spark plugs on the drivers side. I decided to look at the passenger side and noticed it was also leaking from that side to. it seems like they all have a very little leak. There is no dripping yet but I want to get this fixed. Is itpossible that all the rings or tubes would leak? What are the chances that all the spark plug sealss failed. I just bought the car a year ago and it only has 47000 miles so I imagine the plugs are still the original ones.

If anyone could help me out on what steps i should take to find the problem it would be appreciated.