Security Incidents mailing list archives

RE: Bizarre traffic


From: "David Gillett" <gillettdavid () fhda edu>
Date: Mon, 13 Feb 2006 09:14:29 -0800

  A bad NIC is one of the other possibilities on my list. 

  I have difficulty imagining a router or switch doing this
*only* to a specific client machine.

David Gillett


-----Original Message-----
From: Brian Rectanus [mailto:brectanu () gmail com] 
Sent: Friday, February 10, 2006 9:15 PM
To: incidents () securityfocus com
Subject: Re: Bizarre traffic

With it cooresponding to network disruptions, similar IPs on 
your net and conversations looking normal otherwise, have you 
considered it a router/switch corrupting packets?  Or even 
the a bad NIC in a machine?

-B

On 2/9/06, David Gillett <gillettdavid () fhda edu> wrote:
  Does anybody know of anything (malware, hackware, other?) 
that would 
cause a machine to put out traffic with the first octet of the 
destination address (re)set to ZERO?

  The traffic I saw all was headed for port 443, and wasn't 
decipherable.  The variation in packet size looked like a real 
conversation, although return packets (if any) weren't passing my 
sniffer.  The destination addresses, sans the bogus first octet, 
looked like addresses of a couple of real internal servers (source 
address was internal) -- which, however, do not have HTTPS service 
active.

  [This traffic correlated with various intermittent disruptions of 
our network, which stopped when the source machine dropped off the 
network.  It later reappeared -- and so did a brief 
disruption -- long 
enough for me to pinpoint and ban it.]

David Gillett






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