>The attack described just now, is that this vulnerability combined with >the traditional "birthday" attack scenario allows another form of >attack. The birthday attacks in general are still possible on any DNS >server which doesn't randomize source ports, but may be more difficult >to conduct than this new attack. (I'm not sure, I haven't run the >numbers.) Thank you for the clarification, Tim. That is exactly what I wanted to say. :) By the way, as regards recent Bind 9, birthday attack is much more difficult to conduct because even if the attacker sends multiple simultaneous recursive queries, Bind 9 aggregates these queries. In addition, there is a patch written by Jinmei-san for Bind 9.4.0 (current release) to randomize source ports. http://www.jinmei.org/bind-9.4.0-portpool.patch http://member.wide.ad.jp/tr/wide-tr-dns-bind9-portpool-01.txt (technical report from WIDE project in Japanese) Makoto Shiotsuki
