North American Network Operators Group

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Re: DNS: Definitely Not Safe?

  • From: Peter Dambier
  • Date: Wed Feb 14 09:11:14 2007

Security of DNS servers is an issue for network operators, thus pertaining to NANOG on-topics. This article shows a security-officer view of the recent DNS attacks.

"Despite well-publicized attacks on domain name servers in 2000 and 2001, evidence suggests that many companies simply have not taken the steps necessary to protect this vital part of their networks. Experts differ on just how much danger companies generally face. However, they seem to agree that, depending on the circumstances and the company, the results could include electronic attacks and unknowingly providing confidential information to competitors."

I am not shure wether the author isn't walking beside his shoes.

DNS is like a telephone book.

Yes it is dangerous to have your telephone number listed in
a publicly available book. We should forbid telephone books
and the world would me much safer?

If you are afraid of people using axfr to slave a nameserver
then dont publish it. Use /etc/hosts not DNS and best dont
tell anybody your ip-address.

In some places (Africa ?) root-servers may be difficult to
see, so why not clone them and have the root on your local
network? If they are attacked again - no problem. Your
personal root-server will survive at least a month without
them. Of course you need axfr transfers to do that.

I dont know how you can use axfr transfers to DoS somebody
else but yourself. It is a tcp connection after all. You
need to be connected. Overloading electricity supply like
the NSA tries to do is a lot more efficent.

Rests recursive nameservers, resolvers. Yes, that could
help. Forbid all publicly available resolvers including
those of your ISP then attackers, mostly running windows
in their botnets will not find their targets any longer.

The big problem is IT-personal relying on windows for
their backbones. You cannot help them, only an attack

I remember companies used to run their own internal
nameservers. Why dont they do it any longer? DNS has
become so much more relyable that they dont need to.

Kind regards Peter and Karin -- Peter and Karin Dambier Cesidian Root - Radice Cesidiana Rimbacher-Strasse 16 D-69509 Moerlenbach-Bonsweiher +49(6209)795-816 (Telekom) +49(6252)750-308 (VoIP: mail: [email protected] mail: [email protected]