Re: The out-of-domain NS registration attack

[sanford.whiteman () INTERNAL CONVEY COM (Sanford Whiteman)]

Dave, you are certainly correct.  We just performed a giant name server
migration and can verify that NSI's database has dual primary keys, or
what-have-you, that prevent the attack.  A name server's IP address can only
be associated with one NIC handle...once you bind a hostname to the IP, the
hostname is bound to the NIC handle as well.  The only way to change this
information is to be the contact for the name server's domain.  No one else
can duplicate either of the keys.

Sandy

-----Original Message-----
From: Bugtraq List [mailto:BUGTRAQ () SECURITYFOCUS COM]On Behalf Of David,
Gover
Sent: Wednesday, March 15, 2000 3:55 AM
To: BUGTRAQ () SECURITYFOCUS COM
Subject: Re: The out-of-domain NS registration attack

On Tue, 14 Mar 2000, D. J. Bernstein wrote:

> Let's say an attacker wants to steal your mail to hotmail.com.

[snip]

> The attacker then registers a new domain with NSI, using ns1.jsnet.com
> as the domain's server name, but his own IP address for ns1.jsnet.com:
>
>    zerosecurity.com NS ns1.jsnet.com
>    ns1.jsnet.com A 5.6.7.8

Afaik, you will be unable to do this, as for each host record at NSI, they
also hold an IP address. When you specify ns1.jsnet.com as an NS for
your domain, the IP address NSI already holds for this hostname is used.
Even if you are able to specify a different address for 'ns1.jsnet.com' on
your application form, NSI (should|will) either reject it, or
ns1.jsnet.com will have both the old, and new A record on NSI's
nameservers.  Couldn't this lead to other major problems apart from
stealing email?

It's a while since I've registered a domain name with NSI, and so things
may work slightly differently, than I have stated or expect..

Dave