Deflecting Bogus Queries -- Machine Under Attack, PLEASE HELP.

[Dan Mahoney, System Admin]

On Thu, 5 Aug 2004, Sten Carlsen wrote:

>
>
> Dan Mahoney, System Admin wrote:
>
>> On Thu, 5 Aug 2004, Sten Carlsen wrote:
>> 
>>> Hi
>>> 
>>> How about making a local zone for which you are authorative and return 
>>> "no A record present". At least it will stop any recursive lookups.
>> 
>> 
>> I (or the customer, actually) *am* authoritative for elephaunt.org. These 
>> are not recursive lookups.  But I'm sure this is setting off firewall logs 
>> at all the spoofed hosts, no matter what I return.
>> 
>> That's why I wanted the "silent ignore" option.  You can do it per IP, but 
>> not per zone.
>> 
>> -Dan
>> 
> Ok, then I guess you just have to serve out answers, I doubt you could 
> determine which question is "real" and which is "noise".

Anything for the non-existent zone spaz.elephaunt.org is noise.

-Dan

>
>>> 
>>> 
>>> Dan Mahoney wrote:
>>> 
>>>> I'm presently dealing with a DNS server that's under attack, and is
>>>> being made to spew out DNS responses all over the internet, hundreds,
>>>> maybe thousands a second.
>>>> 
>>>> I cannot trace the source IP to log it or ban it because it's
>>>> obviously forged, and there's enough DNS traffic on the wire that it's
>>>> suitably masked.
>>>> 
>>>> I'd like to know if I can just somehow set bind to DROP all queries
>>>> for the domain in question.  No response, no nothing, just silently
>>>> ignore them.  It won't make the attack stop, but at least it'll stop
>>>> me from being used as a reflector.
>>>> 
>>>> These domains don't even exist.  I thought about redirecting an NS
>>>> record for these subdomains elsewhere, but it wouldn't really matter
>>>> since I think the attack is ignoring true DNS.
>>>> 
>>>> Here's a quick log:
>>>> 
>>>> Jul 30 19:36:18 cp named[6408]: client 24.158.63.9#53: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 205.152.37.254#42256: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.82.0.5#32770: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 66.215.64.14#54971: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 216.158.48.2#1041: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 24.25.35.64#48487: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 205.188.118.92#33518: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 206.13.30.27#9904: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 167.206.3.232#32772: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 216.68.4.20#3408: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 209.244.4.171#32776: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.46.144.5#34740: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.46.144.5#34740: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.46.144.5#34740: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.46.144.5#34740: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.46.144.5#34740: query:
>>>> spasm.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 67.32.118.46#32819: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.82.0.5#32770: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.39.224.5#44247: query:
>>>> spaz.elephaunt.org IN A
>>>> Jul 30 19:36:18 cp named[6408]: client 68.46.144.5#34740: query:
>>>> spasm.elephaunt.org IN A
>>>> 
>>>> Replies to this address are appreciated, although I will of course
>>>> check the group.  danm at ezzi dot net is also useful.
>>>> 
>>>> 
>>> 
>>> 
>> 
>> -- 
>> 
>> "We need another cat.  This one's retarded."
>> 
>> -Cali, March 8, 2003 (3:43 AM)
>> 
>> --------Dan Mahoney--------
>> Techie,  Sysadmin,  WebGeek
>> Gushi on efnet/undernet IRC
>> ICQ: 13735144   AIM: LarpGM
>> Site:  http://www.gushi.org
>> ---------------------------
>> 
>
> -- Best regards
>
> Sten Carlsen
>
> Let HIM who has an empty INBOX send the first mail.
>

--

"Be happy.  Try not to hurt each other.  Hope you fall in love."

--Mallory, Family Ties Finale (on the meaning of life)

--------Dan Mahoney--------
Techie,  Sysadmin,  WebGeek
Gushi on efnet/undernet IRC
ICQ: 13735144   AIM: LarpGM
Site:  http://www.gushi.org
---------------------------