IP ID could allow to scan a masquerade network.

From: Elie aka \ (elieat_private)
Date: Mon Nov 05 2001 - 17:20:43 PST

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    Hello,
    
    I was working on a new implementation of the IPID scann (also known has
    idle scan in the nmap man page or  pixie-scan as i call it)
    During my test I think I discover a new way to use this type of scan :
    
    Synopsis
      -------------
    
    Using the gateway of a masquerade network as a witness (relay host) for the 
    Pixie-scan,
    allow remote scanning of the private network.
    
    Details
    -----------
    
    On some stack implementation the IP ID field is incremental so by sending a 
    spoofed SYN
    packet to the gatway from a private network box and by comparing after the 
    IP ID value
    you could remotely know witch service are open on this intranet  computer 
    even if this one is masquerade.
    Of course the pixie-scan is a well known technique but this is this 
    utilisation that is new.
    For more detail about the pixie-scan i have written a paper witch will  be 
    available around tomorow
    evening at the following url : http://www.bursztein.net/secu/pixie.html
    
    Affected version
    -----------------------
    
    I have tested the pixie-scan against with success :
    
    - Win 2K service pack
    - 3com Netbuilder
    
    unsuccessfull attempt :
    
    - Linux 2.4.x
    
    
    
    sincerly,
    
    Elie aka "Lupin" Bursztein
    ___________________________
    icq  : 32228319
    mail : secuat_private
    web  : www.bursztein.net/secu
    ___________________________
    "He feel safe and at this very moment, i was lost... "
    



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