Unusual IN ANY DNS Traffic

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1

Since about 03:00 UTC this morning I've been seeing a huge increase in "IN
ANY" requests for "msn.com.". While my name servers have not seen much, if
any, "IN ANY" queries in the past, now I'm seeing ~ 50 queries/second. I'll
include a tcpdump sample below.
Actually, while I was writing this post the queries seem to have stopped
(15:05 UTC).
Is this typical of a botnet or some worm propogating? Any experience in this
type of traffic would be very much appreciated.

-Doug

==== tcpdump - times in EDT ====

# tcpdump -nn dst port 53 | grep 'ANY'
tcpdump: listening on eth0
10:27:16.748561 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 6+ ANY? msn.com. (25)
(DF)
10:27:16.751724 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 15+ ANY? msn.com. (25)
(DF)
10:27:16.758276 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 16+ ANY? msn.com. (25)
(DF)
10:27:16.758440 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 3+ ANY? msn.com. (25)
(DF)
10:27:16.758443 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 10+ ANY? msn.com. (25)
(DF)
10:27:16.759799 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 16+ ANY? msn.com. (25)
(DF)
10:27:16.761228 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 10+ ANY? msn.com. (25)
(DF)
10:27:16.762209 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 6+ ANY? msn.com. (25)
(DF)
10:27:16.764992 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 7+ ANY? msn.com. (25)
(DF)
10:27:16.765981 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 16+ ANY? msn.com. (25)
(DF)
10:27:16.766676 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 6+ ANY? msn.com. (25)
(DF)
10:27:16.766798 66.59.xxx.xxx.53 > 205.166.xxx.xxx.53: 8+ ANY? msn.com. (25)
(DF)

2

One thing I've noticed that likes to generate ANY queries is Qmail...

Duane W.

3

I guess I should've stated that these are almost all some DSL customers on our
network using their assigned DNS servers, but this traffic is just completely
out of normal; especially since they were all looking for "msn.com.".
Another thing that is quite odd (to me) is that the source port is all port
53; I thought that normal clients would use a random high port to do queries
from.

-Doug

4

Indeed moderns versions of BIND default to high ports for DNS queries as
well unless configured otherwise. I think old versions of BIND and the odd
firewall product were the main thing doing source port 53 queries.

I was going to suggest email servers as a possible cause -- I think
probably you'll have to speak to a customer if it still persists. Make sure
they haven't been owned. Might just have been a spam run or mailshot with
"msn.com" as the reply, and you discovering how many email servers are out
there or similar.

I suspect you're correct; these are probably some DSL customers who have
"0wn3d" by either a virus or malware and have just been "turned on" to spam
domains at "msn.com". Unfortunately we don't do protocol graphs on our major
routers or else I would have been able to see a spike of port 25 traffic if
it had existed - we just graph our DNS server query which is why I noticed
the jump.

I assume your not using something daft like MS DNS server, but a recent
BIND or DJB cache.

Also correct; we're running BIND 9.2.2 and I parse the query logs to see what
kind of traffic we're getting via the different query types.

-Doug