On Sun, 2006-10-29 at 09:40 -0600, Gadi Evron wrote:
On Sun, 29 Oct 2006, Douglas Otis wrote:
How would you identify and quell an SPF attack in progress?
Okay, now I understand.
You speak of an attack specifically utilizing SPF, not of how SPF relates to botnets or attack traceback.
The same could be said for web servers, databases behind them, DNS-SEC crypto calculations, etc.
The described indirect SPF attack does not utilize packet source spoofing, and yet may achieve amplifications greater than 1000:1. The resources to stage an SPF attack would be the ever present spam, where about 70% this is coming from Botnets. In the case of spam related SPF, the attack itself can be virtually free. While also consuming an attacker's resources, a DNS reflective attack with spoofed source packets represents a far lower impact when compared to the SPF attack. SPF represents a grave danger without means for mitigation. The same can not be said for these other protocols. -Doug