When I've had an overtightened oil filter and/or the absence of a wrench, I've always resorted to a method that a motorcycle mechanic showed me once. Get a medium sized phillips screwdriver with a fairly sharp point and with a few taps of a hammer, puncture thru one side of the oil filter to the other side (obviously, make sure you have a pan underneath). Once it's through, just a good tug on the screwdriver handle (as if it were a handle on an old sailing ship wheel) will typically rotate the oil filter loose. You can hand-loosen it once it's free.