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<TITLE>Re: [AusNOG] DNS Cache Poisoning Vulnerability</TITLE>
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<P><FONT SIZE=2>I'll get the guys to check - they assured me our DNS servers were upgraded a few weeks back, so this is a little strange...<BR>
<BR>
Bob Purdon<BR>
General Manager,<BR>
Managed Infrastructure,<BR>
PIPE Networks Limited (ASX:pwk)<BR>
<BR>
Phone : +61 7 3233 9844<BR>
Fax : +61 7 3233 9885<BR>
Web : www.pipenetworks.com<BR>
<BR>
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----- Original Message -----<BR>
From: ausnog-bounces@lists.ausnog.net <ausnog-bounces@lists.ausnog.net><BR>
To: ausnog@ausnog.net <ausnog@ausnog.net><BR>
Sent: Fri Aug 08 08:05:06 2008<BR>
Subject: Re: [AusNOG] DNS Cache Poisoning Vulnerability<BR>
<BR>
That is quite a handy and easy to use tool. ausnog.net's nameservers<BR>
need patching though by<BR>
the looks :<BR>
<BR>
"Highly vulnerable.<BR>
<BR>
The servers tested for AUSNOG.NET are highly vulnerable to cache<BR>
poisoning. Immediate action should be taken to rectify the problem."<BR>
<BR>
I'm sure someone on this list will be able to rectify that.<BR>
<BR>
Brent<BR>
<BR>
Brent Paddon<BR>
<BR>
Director | Over the Wire Pty Ltd<BR>
brent.paddon@overthewire.com.au | www.overthewire.com.au<BR>
Phone: 07 3847 9292 | Fax: 07 3847 9696 | Mobile: 0400 2400 54 | Direct: 07 3503 4807<BR>
<BR>
<BR>
<BR>
Kim Davies wrote:<BR>
> Hi folks,<BR>
><BR>
> A number of you have likely heard about this already, but just in case<BR>
> not, this is a fairly serious issue that deserves a few minutes of<BR>
> attention.<BR>
><BR>
> Recently, it was discovered that the amount of entropy in DNS queries is<BR>
> relatively low in typical DNS software implementations, making the<BR>
> ability to spoof answers a fairly trivial exercise that can take as<BR>
> little as a second. This can be used to poison DNS caches, and<BR>
> ultimately introduce false data into the DNS.<BR>
><BR>
> This is important on two distinctly different fronts:<BR>
><BR>
> 1) Recursive name servers should have the maximum amount of entropy<BR>
> to provide the strongest resistance to spoofed DNS responses. This won't<BR>
> solve the problem, but helps mitigate the risk. There are<BR>
> patches for BIND etc. now available to randomise the source port of<BR>
> queries to aid this. To test a recursive name server you can use<BR>
> the tool at<BR>
><BR>
> <A HREF="https://www.dns-oarc.net/oarc/services/dnsentropy">https://www.dns-oarc.net/oarc/services/dnsentropy</A><BR>
><BR>
> 2) For domain registrants, the authoritative name server for your<BR>
> domain can be affected if they also offer recursive name service.<BR>
> The effects of cache poisoning can therefore introduce false<BR>
> data into your zone. To test for vulnerable servers, there is a<BR>
> new tool at<BR>
><BR>
> <A HREF="http://recursive.iana.org/">http://recursive.iana.org/</A><BR>
><BR>
> The solution to this problem is to separate recursive and<BR>
> authoritative name service from one another.<BR>
><BR>
> There is also an FAQ, focused on part 2, at<BR>
> <A HREF="http://www.iana.org/reports/2008/cross-pollination-faq.html">http://www.iana.org/reports/2008/cross-pollination-faq.html</A><BR>
><BR>
> cheers,<BR>
><BR>
> kim<BR>
> _______________________________________________<BR>
> AusNOG mailing list<BR>
> AusNOG@lists.ausnog.net<BR>
> <A HREF="http://lists.ausnog.net/mailman/listinfo/ausnog">http://lists.ausnog.net/mailman/listinfo/ausnog</A><BR>
> <BR>
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