(Im)possibility of a coordinated attack Faustine van der Grijn Abstract: Making use of epistemic logic it is provable that whenever the smallest uncertainty of message delivery is present, common knowledge via communication is impossible. This implies that a coordinated attack, which demands common knowledge, really can never take place. But there might be possibilities for a coordinated attack when you drop the demand of common knowledge and have a look at the probabilities of proper message delivery. A tentative start is made to develop a theory to explore this.