Bugtraq mailing list archives
Re: recursive DNS servers DDoS as a growing DDoS problem
From: "mike davis" <phar () stonedcoder org>
Date: Mon, 27 Mar 2006 18:27:49 -0500
If you have a 20,000 bot botnet and each bot has 2 defined recursive dnsservers that it is allowed to use and these bots are on the local subnet (ieBCP38 is implimented at the gateway but not at every router) then howexactly is locking down recursive servers so you can only use yours going tosolve anything?
uh... caching maybe?... the second field of your answer section when using dig..
To fix DNS we would have to eliminate it's use of UDP which means pretty much all internet software would need to be rewritten, that is an unrealistic goal.
no, its not, and it doesnt require that all internet sofware be rewritten, it means that they either need to be recompiled, or just have the dynamicly linked library they use for dns resolution to be replaced..
Locking down recursive servers may increase the number of machines required to create a flood but again a large botnet will have no problem so that's no solution either. BCP38 will accomplish the same ineffective goal but at least has the added potential to reduce non DNSrelated spoofed attacks at the same time making it easier to at least trackdown the sources of a distributed flood at least to the provider level if not to the exact IP.
i think its pretty obvious that locking down dns servers at least brings the DNS attacks down to the same problem weve always had.. that being good old fashioned udp packeting. and at that point.. why bother using dns..
-phar
Current thread:
- Re: recursive DNS servers DDoS as a growing DDoS problem, (continued)
- Message not available
- Re: recursive DNS servers DDoS as a growing DDoS problem Gadi Evron (Mar 02)
- Re: recursive DNS servers DDoS as a growing DDoS problem Ventsislav Genchev (Mar 10)
- Re: recursive DNS servers DDoS as a growing DDoS problem Robert Story (Mar 17)
- Re: recursive DNS servers DDoS as a growing DDoS problem Michael Sierchio (Mar 20)
- Re: recursive DNS servers DDoS as a growing DDoS problem Robert Story (Mar 17)
- Re: recursive DNS servers DDoS as a growing DDoS problem Chris Thompson (Mar 23)
- Re: recursive DNS servers DDoS as a growing DDoS problem Anton Ivanov (Mar 27)
- Re: recursive DNS servers DDoS as a growing DDoS problem MaddHatter (Mar 25)
- Re: recursive DNS servers DDoS as a growing DDoS problem Gadi Evron (Mar 25)
- Re: recursive DNS servers DDoS as a growing DDoS problem Geo. (Mar 27)
- Re: recursive DNS servers DDoS as a growing DDoS problem mike davis (Mar 30)
- Re: recursive DNS servers DDoS as a growing DDoS problem Geo. (Mar 30)
- Re: recursive DNS servers DDoS as a growing DDoS problem gboyce (Mar 30)
- Re: recursive DNS servers DDoS as a growing DDoS problem Stephen Samuel (Mar 30)
- Re: recursive DNS servers DDoS as a growing DDoS problem Gadi Evron (Mar 25)