FWIW, we've seen the exact activity you outline below in the wild. In this case, it was associated with spam.
-----Original Message----- From: Geo. [mailto:[EMAIL PROTECTED] Sent: Wednesday, March 08, 2006 1:27 PM To: bugtraq@securityfocus.com Cc: full-disclosure@lists.grok.org.uk Subject: RE: [Full-disclosure] Re: recursive DNS servers DDoS as a growing DDoSproblem >>In the scenario you describe, I cannot see any actual amplification... I'll give you a senario where you can see. lets say you have 2 name servers that are local to you. I setup a domain, example.com. In this domain I create a text record which is 100K in length, I don't know, perhaps I paste the source code to decss in it, whatever it's a big text record. Now I simply spoof a UDP packet using your IP address as the source address and send it to both of your dns servers. This packet is a query for the example.com text record. I have now sent two very small packets and you have received 200K of traffic. That's the amplification, one small udp packet, one large text record in return. Note, I don't have to use your local servers, but this way it makes it more fun to troubleshoot because it looks like you are the cause of your own flooding.. Geo. ********************************************************************************************** IMPORTANT: The contents of this email and any attachments are confidential. They are intended for the named recipient(s) only. If you have received this email in error, please notify the system manager or the sender immediately and do not disclose the contents to anyone or make copies thereof. *** eSafe scanned this email for viruses, vandals, and malicious content. *** ********************************************************************************************** _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
