For the billionth time, DDoS and DoS are both possible against Tor hidden services. Not only can the actual hidden service be DDoSed by a botnet with http spam, but there are also Tor specific attacks that can be carried out. For one DDoSing introduction nodes leads to the hidden service they introduce for being unreachable, for two if the attacker traces to guard nodes they can DDoS them directly. Anybody who says it is impossible to DoS or DDoS hidden services clearly it not very read up on how connections to hidden services work.