Re: FW: Question for DNS pros

[Frank Knobbe <frank () knobbe us>]

On Tue, 2004-08-03 at 15:28, Mark wrote:
> I'd say I'm pretty much seeing the same thing from the following 14 
> addresses.
>
> 202.103.67.196 - appears in dshield   -- check
> 218.25.41.136 - does not appear in dshield   -- check
> 218.30.23.100 - appears in dshield  -- check
> 218.30.23.161 - does not appear in dshield  -- nope
> 218.30.23.162 - appears in dshield -- nope
> 218.75.110.194 - appears in dshield -- check
> 61.135.158.170 - does not appear in dshield -- check
> 61.135.158.171 - appears in dshield -- check
> 61.135.158.28 - appears in dshield  -- check
> 61.135.158.29 - appears in dshield  -- check
> 61.135.158.30 - does not appear in dshield --check 
> 61.135.158.31 - does not appear in dshield -- check
> 61.135.158.34 - does not appear in dshield -- check
> 61.135.158.35 - does not appear in dshield -- check

I see those, and I raise you the following :)

61.145.121.16
63.210.252.135
63.240.26.10
64.170.177.10
66.150.165.7
216.154.239.240
218.75.110.194

> I was guessing it was targeting suspected DNS servers based on it seeing 
> queries at some point.  The target is the dynamic NAT address of one of 
> our internal DNS servers, DNS is the only service running on that box 
> and the only thing that server is allowed to do to the outside world is 
> DNS queries. 

Good, so it appears that the "trigger" are DNS queries then (I confirmed
that internal DNS queries appear from my targeted address as well). This
falls further in line with Paul's findings.

So, I'm speculating that a DNS lookup to something somewhere results in
these IP's performing the observed theatrics (two UDP DNS queries, one
TCP SYN scan with payload, and one ICMP ping).

Let's see:
61.135.158.28-35, 61.135.158.170-171, 61.145.121.16, 202.103.67.196,
218.25.41.136, 218.30.23.161-162, 218.30.23.100, 218.75.110.194 are all
China.

216.154.239.240 - SBC in Irvine
66.150.165.7 - Logical US-AWS NAP through Internap
64.170.177.10 - SBC Interactive through PacBell
63.240.26.10 - CERFnet
63.210.252.135 - Level 3

I'm not sure about my additional IP's as they don't have the same volume
as the initially reported three (218.75.110.194, 61.135.158.28, and
61.135.158.29). I'll take a look at the payload shortly.

If it turns out that all mystery come from China, what do you make out
of that?

Later,
Frank

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