[nsp-sec] List of vulnerable DNS resolvers

[Hank Nussbacher]

On Tue, 22 Jul 2008, Niels Provos wrote:

Kudos to Niels for doing this!

-Hank

> ----------- nsp-security Confidential --------
>
> Hi,
>
> as you know, the DNS flaw was leaked yesterday.   At the moment, ~70%
> of all resolvers on the Internet use static or trivially predictable
> source ports.   These resolvers/NAT devices need to be patched as soon
> as possible.   The CERT reference for this flaw can be found at:
>
> http://www.kb.cert.org/vuls/id/800113
>
> The flaw allows adversaries to inject almost arbitrary A or NS records
> on vulnerable resolvers, e.g. redirect traffic/proxy traffic of
> legitimate domains.
>
> You can find a list of vulnerable resolvers and corresponding AS numbers at:
>
> https://asn.cymru.com/nsp-sec/upload/1216767459.whois.txt
>
> These IP addresses are from recursive resolvers that showed very low
> standard-deviation (<200) in their source ports according to
> measurements conducted by David Dagon and myself over the last 7 days.
> I released a small Python tool that you can use to test your own
> resolver.   You can download it from:
>
>  http://www.monkey.org/~provos/dnspredict.py
>
> Instructions on how to use the tool can be found here:
>
> http://www.provos.org/index.php?/archives/42-DNS-and-Randomness.html
>
> Please, let me know if you have any questions.
>
> Thank you,
> Niels.
>
>
> _______________________________________________
> nsp-security mailing list
> nsp-security at puck.nether.net
> https://puck.nether.net/mailman/listinfo/nsp-security
>
> Please do not Forward, CC, or BCC this E-mail outside of the nsp-security
> community. Confidentiality is essential for effective Internet security counter-measures.
> _______________________________________________
>