DNS Amplification attack?

jay at miscreant.org jay at miscreant.org
Tue Jan 20 21:08:25 CST 2009


> On Tue, Jan 20, 2009 at 9:16 PM, Kameron Gasso <kgasso-lists at visp.net> wrote:

> We're also seeing a great number of these, but the idiots spoofing the
> queries are hitting several non-recursive nameservers we host - and only
> generating 59-byte "REFUSED" replies.
>
> Looks like they probably just grabbed a bunch of DNS hosts out of WHOIS
> and hoped that they were recursive resolvers.

First post to this list, play nice :)

Are you sure about this? I'm seeing these requests on /every/  
(unrelated) NS I have access to, which numbers several dozen, in  
various countries across the world, and from various registries (.net,  
.org, .com.au). The spread of servers I've checked is so random that  
I'm wondering just how many NS records they've laid their hands on.

I've also noticed that on a server running BIND 9.3.4-P1 with  
recursion disabled, they're still appear to be getting the list of  
root NS's from cache, which is a 272-byte response to a 61-byte  
request, which by my definition is an amplification.

Cheers,

Jay





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