[Full-disclosure] DNS Smurf revisited
From: Ian Gulliver (ian-fulldisclosure_at_penguinhosting.net)
Date: 05/27/05
- Previous message: Barrie Dempster: "Re: [Full-disclosure] Not even the NSA can get it right"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]
Date: Fri, 27 May 2005 10:28:37 -0400 To: full-disclosure@lists.grok.org.uk
DNS smurf is old news:
http://www.s0ftpj.org/docs/spj-002-000.txt
http://www.ciac.org/ciac/bulletins/j-063.shtml
However, as ISPs continue to operate networks that let spoofed packets
out this issue deserves a little publicity again.
10:17:07.641061 IP (tos 0x0, ttl 64, id 46429, offset 0, flags [DF], length: 49) XXXXXXXXXXXXX.44295 > c.gtld-servers.net.domain: [udp sum ok] 18297 ANY? org. (21)
10:17:07.673800 IP (tos 0x0, ttl 43, id 0, offset 0, flags [DF], length: 468) c.gtld-servers.net.domain > XXXXXXXXXXXXX.44295: 18297- 0/13/13 (440)
% echo "2 k 468 49 / p" | dc
9.55
That's a 9.5X amplification of outgoing traffic; you can probably break
10X with a little more work on the query and nameserver choices.
SOLUTIONS
---------
ISPs: Drop outgoing packets that don't originate from within your
network. You should already be doing this, as it stops a variety of
other attacks.
NS operators: Ratelimit?
Attached is a modernized proof of concept.
-- Ian Gulliver Penguin Hosting "Failure is not an option; it comes bundled with your Microsoft products."
_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/
- text/x-csrc attachment: dnos.c
- application/pgp-signature attachment: Digital signature
- Previous message: Barrie Dempster: "Re: [Full-disclosure] Not even the NSA can get it right"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]
Relevant Pages
|
