[bittorrent] NauBTilus - secure and survivable BitTorrent-based system with data updates

BeCe boski_cinek at o2.pl
Sat Sep 5 09:26:12 EDT 2009


Adrian Ulrich wrote:
> Hi,
> 
>> For this reason, anyone who would like to read it,  please send me request (through my e-mail)
>> and I will send you the article.
> 
> I'd be interested to receive a copy.

I've just sent it to you in separate e-mail.

>> As for DHT, the problem is a little more complicated. NauBTilus was
>> designed mainly to handle DDoS attacks. And DHT doesn't solve this
>> problem. It's still possible to attack vulnerable peers that are
>> currently responsible for handling specific torrents.
> 
> Kademlia is pretty robust against (D)DOS-Attacks. DOS'ing a DHT-Node makes
> no sense because the network will recover itself such as it does when someone
> terminates the client. Even DDOSing a large Kademlia-Segment won't do much harm.

Yes, but does it recovers instantly? Because attacker can just switch 
the target for DDoS every time he detects new DHT-node and not give it a 
chance to recover. And that brings another question: can you force user 
to become DHT-node, possible target for DDoS attack, without giving him 
opt-out option? As far as I know this is exactly what happens in DHT. On 
the other hand NauBTilus was designed with easy opt-out option in mind.

> It would make much more sense to DDOS some Seeders.

That is also, in a way, covered in NauBTilus (not in a very pretty way, 
but it should works).

>> Even worse, combining Sybil attack on DHT with other malicious techniques can turn
>> swarm into specific kind of botnet that could be use to perform DDoS
> 
> This is a known problem and not DHT/Sybil specific:
> 
> So an evil node could just take a sha1 that is near to some popular info_hash and
> hand out wrong IPs (= IPs that point to a target) (-> Sybil)
> 
> But hey: You do not even need to do a sybil attack: Just place a node *somewhere* in the network
> and always send a get_peers response. Some clients out there are willing to accept responses
> to unasked questions :-)

I was rather thinking about many DHT nodes for single machines used to 
route all possible traffic they get into victims machine.

> ..Or you could join the network to spread the target-IPs via PEX

Which is far more harder to do if don't have a lot of other peers IP 
addresses and they're not willing to pass provided victims IP to other 
neighbors.

Just to clear something out: I agree that BT is doing its job pretty 
well. NauBTilus wasn't design to compete with BitTorrent. It was design 
to serve different purpose than BitTorrent.
-- 
Regards,
Marcin



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