Re: Weak TCP Sequence Numbers in Sonicwall SOHO Firewall

From: Barney Wolff (barneyat_private)
Date: Wed Jul 25 2001 - 18:47:32 PDT

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    You're nmap'ing from inside, right?  Nobody from outside should
    be able to connect to the Sonicwall at all.  Sequence numbers
    for connections *across* the NAT depend on the endpoint hosts,
    not the NAT box.  So this is a risk only if you have enemies
    already inside your house.
    
    Barney Wolff
    
    On Wed, Jul 25, 2001 at 05:17:28PM -0600, Dan Ferris wrote:
    > This may not seem bad, but to me it seems that this defeats the point of NAT
    > if somebody can steal your sessions.  Note the section on TCP sequence
    > prediction.  This was a Sonicwall SOHO firewall.
    > 
    > =======
    > Host  (192.168.1.254) appears to be up ... good.
    > Initiating SYN half-open stealth scan against  (192.168.1.254)
    > Adding TCP port 80 (state open).
    > The SYN scan took 8 seconds to scan 1523 ports.
    > For OSScan assuming that port 80 is open and port 1 is closed and neither
    > are firewalled
    > Interesting ports on  (192.168.1.254):
    > (The 1518 ports scanned but not shown below are in state: closed)
    > Port       State       Service
    > 23/tcp     filtered    telnet
    > 67/tcp     filtered    bootps
    > 80/tcp     open        http
    > 137/tcp    filtered    netbios-ns
    > 514/tcp    filtered    shell
    > 
    > TCP Sequence Prediction: Class=64K rule
    >                          Difficulty=1 (Trivial joke)
    



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