If the witness is attacked by DDOS, and the 12 witnesses are attacked and unable to issue witness blocks, what shall we do? Does byteball's network stop? Will it be as unsafe as DPOS?
Witnesses are likely hidden with TOR so you won't be able to find them even with the complicity of the hub they are connected to. In the case you still managed to find their IP, you would need a huge DDOS power to take all them down since they are hosted all around the world on several networks all having their own DDOS protections.