[PseudoFenton]

Failing that, if your take on what constitutes an attack is so broad - then I suggest continual exposure to said 'attacks'. Then wait for them to dehydrate and become sleep deprived (an attack wakes you up), the attrition of FP loss that they can't restore due to this ability will eventually make them pass-out and then die. It may take a while, but poisoning the air is an easy way to keep a large area "attacked", and if that counts, so should using low level radiation (it might injure you, so it's an 'attack'). Its then very easy for the aggressors to use gas-masks for the poison and shielding (and/or shift work) for the radiation to avoid any harm themselves.

Also, if there is a means that allows an insubstantial entity to affect the substantial world, the reverse is also logically true and you can just use those - if this isn't the case, then who cares? If they can't do anything when insubstantial, then they're effectively removed from any and all situations where someone cares to even provide a token amount of "attacks" their way - which as its not based on the severity of the attack, is really easy to do!