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Hello,<br>
<br>
My question is not related to NSD in particular, but I have seen
here on the list a lot of people that work for TLDs and other
Registrars and Registry operators I thought it would be a good place
to ask this question. It is about DNS though, not completely off
topic :).<br>
<br>
I have encountered in my DNS studies a few name servers that let you
transfer zones they are authoritative for. The name servers I am
talking about are not under my control. I have noticed that in the
majority of cases ns2.*, or whatever name the second NS has, lets
you perform the zone transfer. This led me to the conclusion that
the sys admins don't pay enough attention or don't really know or
understand DNS technology. It is not my intention to offend any sys
admin. I am just saying. Or maybe the people that set up those
servers are not sys admins. Who knows.<br>
<br>
Do you consider the above as being a security vulnerability?<br>
<br>
My thoughts on this.
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This isn’t necessarily bad if the only information provided is
related to systems that are connected to the Internet and have valid
hostnames, although it makes it that much easier for attackers to
find potential targets. Almost all the time people use suggestive
names like splunk, nagios, cpanel, switch-c2950, etc. That would
give an attacker a good start. But on the other hand it can find
those by himself by querying the name server for those names.<br>
<br>
In some cases, as I have seen, there are entries that have private
addresses. I consider this as being quite bad because it reveals the
private address space of the company's/institution's IT
infrastructure. <br>
<br>
What about open resolvers? I am not talking here about OpenDNS or
Google, who monitor their infrastructure and maybe they even rate
limit the queries per source IP address if too many come from one
particular source. I am talking about servers that are not being
monitored. I say this because if you monitor your servers and if you
understand the DNS technology you can see that someone has AXFR-ed
your zone or queried whatever.domain.com recursively using your name
server and put an end to it. <br>
<br>
What are your thoughts on this matters? <br>
<br>
Cheers and Goodwill,<br>
Valentin Bud <br>
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