- Nice amount of exit relays
The low bandwidth attacks do need neither high bandwidth nor low latency which would be problematic for many other types of DoS / DDoS attacks. On the other side the list of exit relays is known so it makes blocking of an ongoing attack easier.
- Is there any other serious obstacle for such attacks over Tor?
- Are there known cases when was the Tor network abused for a successful low bandwidth attack?
- Were any counter-measures against such abuse considered? I can imagine for example limiting number of exit-relays a single Tor client can create circuits to though such a limitation could be overcame by modifying the Tor client or running multiple instances of it.
There is a related question: mitigating anonymous DOS (tor combined with pyloris)