Actually, what we are seeing does not appear to be an amplification attack. It appears to be a request flood from infected machines. We have anti-spoofing filters on our upstream connections as well as our subscriber's access lines. The source addresses are not spoofed. They are valid subscriber source IP's. Based on some cached entries I have found in other nameservers, CTRC.CC was apparently hacked and was delegating a number of subdomains to another nameserver that was issuing the 4K TXT record. The delegation has now been removed, and the nameserver they were delegated to appears to be offline. --Paul -----Original Message----- From: william(at)elan.net [mailto:william@elan.net] Sent: Friday, February 24, 2006 9:47 AM To: Estes, Paul Cc: nanog@merit.edu Subject: Re: DNS deluge for x.p.ctrc.cc On Fri, 24 Feb 2006, Estes, Paul wrote:

We have recently noticed a deluge of DNS requests for "ANY ANY" records

They are trying to abuse similar holes that caused most of us add "no ip redirects" and "no ip directed broadcast" to routers, but this time its about dns

of x.p.ctrc.cc. The requests are coming from thousands of sources, mostly our own customers.

Why am I not surprised ....

There are currently no records for x.p.ctrc.cc, or even for p.ctrc.cc.

A google search for x.p.ctrc.cc comes up with only 2 hits. One is a DNS log showing references to this name. The other one shows that somebody else is seeing the same behavior as we are:

http://weblog.barnet.com.au/edwin/cat_networking.html

However, this site has the benefit or providing a history that

had (a week ago) delegated NS record pointing to 321blowjob.com. At

http://www.completewhois.com/cgi-bin/whois.cgi?query=28242102&options=re trieve I don't think this is a hacker-setup domain, probably their dns servers were at some point hacked. They are associated with legacy ip block 192.238.16.0/21. It is also notable that CTRC.CC A record points to 192.168.202.72 p.ctrc.cc that

time, 321blowjob.com's nameserver was responding with a TXT record for x.p.ctrc.cc.

It would appear that ctrc.cc was the victim of some DNS hijacking. Whatever malware is attempting to lookup this name, however, is doing so at a horrific rate. I have some addresses that have made >250000 requests for this name in a short period of time.

I was thinking that I could simply put an authoritative zone for p.ctrc.cc in our nameservers and return something for the lookups

You might want to consider returning the same thing in lookups as ctrc.cc themselves have for direct A lookups... , [snip]