RE: Spoofed TCP SYNs w/Winsize 55808 (was: Help with an odd log f ile...)

From: Taylor, David (ltrat_private)
Date: Wed Jun 18 2003 - 03:31:21 PDT

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    The fact that some of the source ip addresses are real addresses doesn't
    actually mean the packet came from that address.  I'm running a LaBrea
    Tarpit in hopes of sticking one of these connections and have had no luck so
    far.  Half the time I get an ICMP UNREACHABLE returned from my SYN/ACK.
    Sometimes I get an RST and sometimes it just disappears into thin air.
    
    One thing that I really don't understand about this windows size thingy is
    all the focus is being set just on that window size.  I'm curious if this
    window size is just some kind of pre-attack probe putting zombies into
    'attack mode' where they would then listen for say window size of 60000 to
    launch the attack or telling it to arm itself and opening up a port for
    further instructions.  Who knows. One thing that is for certain though, for
    the trojan/whatever to get planted in the first place it has to be done via
    exploitable means via conventional methods such as netbios exploitation,
    email attachments, etc.
    
    I'm currently filtering out common worm ports on my tarpit in hopes of
    identifying other anomalies that don't fit into the normal weird categories.
    If I come up with anything I'll let everyone know.
    
    Dave 
    
    -----Original Message-----
    From: Anders Reed Mohn [mailto:anders_rmat_private] 
    Sent: Tuesday, June 17, 2003 6:29 AM
    To: incidentsat_private
    Subject: Re: Spoofed TCP SYNs w/Winsize 55808 (was: Help with an odd log
    file...)
    
    
    Forgive me if this just ends up in a stupid question, but having watched
    this thread for a while now, it strikes me 
    as odd that noone has been able to trace the origin of any 
    of these packets yet.
    These packets are now widely known (and have been 
    discussed on other lists, in the news etc, as well), and there 
    are quite a few network admins aware of this.
    
    Is it not possible for a few to get together and track down at 
    least _one_ source computer?
    
    It seems to me that you are all putting a awful lot of effort in logging and
    tracking and making statistics. This is of course a good thing, but if we
    want to figure this thing out, there's more that need to be done.
    
    I know.. spoofed addresses.. but that
    does not mean we cannot trace packets to a certain extent.
    A shitty job, but unfortunately the only way of going about this, if we want
    to track it down for real. Also, it seems from some posters that not all
    sources are spoofed.
    
    Are you guys talking to your ISP's about this? I am sure the average ISP has
    at least one techhead that would be interested in digging a little in this,
    and I am guessing that several ISPs read this list as well. I'm not
    currently working as a network admin, so I'm not in a position to do much
    hunting in logs myself, unfortunately.
     
    So, what's happenin' dudes? Can we mount a common effort to track 
    this down?
    Any ISP techs reading this, who sees these packets coming out from their
    networks? Do you contact the "offenders"?
    
    Cheers,
    Anders :)
    
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