Full Disclosure mailing list archives

RE: Re: ICMP DestinationUnreachable Port Unreachable


From: "Fetch, Brandon" <BFetch () texpac com>
Date: Wed, 16 Aug 2006 17:40:39 -0400

Isn't there a new Trojan that's using ICMP to send back it's pilfered
data?  It's encrypted (if I remember correctly) so no clear-text reading
of what's sent and that may explain why you're seeing the random data.

The padding of the same characters in individual packets may designate
start/stop points in the transmission segments.

Just my $.02...

Brandon

-----Original Message-----
From: full-disclosure-bounces () lists grok org uk
[mailto:full-disclosure-bounces () lists grok org uk] On Behalf Of Adriel
T. Desautels
Sent: Wednesday, August 16, 2006 10:30 AM
To: Adriel T. Desautels
Cc: full-disclosure () lists grok org uk; Valdis.Kletnieks () vt edu
Subject: Re: [Full-disclosure] Re: ICMP DestinationUnreachable Port
Unreachable

Also,
    I failed to mention that they came in bursts of 3 every 5 minutes on
the dot.

Adriel T. Desautels wrote:
Well,
    After over 100,000 alerts each with very different payloads the
traffic stopped. I do have a list of all of the dropped packets from
my
firewall as well and it appears that it was hitting 3 IP addresses
which
are public facing, not just one. The weird part, is that two of those
three aren't even live. So I think that this may have been noise from
a
different attack...

    I'd be very interested in decoding the payloads for some of these.
Anyone here have any tools to do such a decode? I'd rather not do it
manual if at all possible.

Valdis.Kletnieks () vt edu wrote:
  
On Wed, 16 Aug 2006 12:33:13 BST, Barrie Dempster said:
  
    
Although the port 0 in this case is a red herring and irrelevant.
Port 0
itself when used with TCP/UDP (not ICMP!) can actually be used on
the
Internet. A while back I modified netcat and my linux kernel so that
it would
allow usage of port 0 and was able to connect to a remote machine
via TCP
with that port and communicate fine.
    
      
Of course, the poor security geek who see a TCP SYN from port 0 to
port 0,
and then a SYN+ACK reply back, will be going WTF??!? for the rest of
the day. :)

(Another good one to induce head-scratching is anything that does
RFC1644-style T/TCP.  Anytime you see a packet go by in one direction
with
SYN/FIN *and* data, and the reply has SYN/ACK/FIN and data.. ;)
data on it... ;)
  

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-- 

Regards, 
    Adriel T. Desautels
    SNOsoft Research Team
    Office: 617-924-4510 || Mobile : 857-636-8882

    ----------------------------------------------
    Vulnerability Research and Exploit Development





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