MonaB - I don't know what is triggering your cat's attacks. At 7 months old, I would say it's not the usual kitten attack thing.
Is his back rippling? Tail Lashing? If they are, and his ears are back as you say, it sounds like the overstimulation, energy-release type of attack.
I would advise you to try petting him just briefly - a few seconds at a time - to avoid the over stimulation. The second his ears go back, or he shows the other signs, stop petting or cuddling him.
You might keep some catnip toys handy (if he reacts to catnip) to help him discharge the energy on that instead of on your hands.