Linked by Thom Holwerda on Thu 28th Mar 2013 00:36 UTC, submitted by MOS6510
Internet & Networking "The New York Times this morning published a story about the Spamhaus DDoS attack and how CloudFlare helped mitigate it and keep the site online. The Times calls the attack the largest known DDoS attack ever on the Internet. We wrote about the attack last week. At the time, it was a large attack, sending 85Gbps of traffic. Since then, the attack got much worse. Here are some of the technical details of what we've seen."
Permalink for comment 556921
To read all comments associated with this story, please click here.
ssokolow
Member since:
2010-01-21

I just hope the seriousness of this is taken on board and action is taken to mitigate the effectiveness of this attack (there's a few different approaches to this, one of them being to patch the name servers themselves, but personally I'd rather see ISPs, peers and exchanges to add some reverse engineering to their UDP forwarding - in that they only forward UDP packets if the IP address attached can be routed backwards - thus effectively checking if the sender matches what the UDP packet describes).


That's actually a solution to what both the NYT article and one of the commenters on the CloudFlare blog identified as the real problem... that the 'net is full of routers that perform none of the sanity checks which would block such spoofed packets, regardless of what daemon we discover to be exploitable next week.

I'm no expert either, but your solution sounds more complicated (and, hence, more CPU intensive on the routers) than what they were proposing. It sounded like they were just proposing plain old source-interface checking so, when the attacker sends a spoofed packet to a DNS server, one of the border routers along the way drops it for arriving on the wrong interface.

Also, I believe it was the CloudFlare commenter who pointed out that this isn't the first attack of this kind. Before spoofed UDP flooding via DNS, there was spoofed SYN flooding.

Reply Parent Score: 2