> Since nmap recognizes a lot of routers and switches it is 
> probably or an 
> exotic router, a vpn or a printer. (I recently came up at a 
> bunch of HP 
> printers not recognized by nmap...) But I'm not aware of canned 
> scripts/exploits to exploit TCP sequence numbers 
> vulnerability but I don't 
> think it would be of much resort for you apart if there are 
> servers denying 
> service to external networks...

Active OS rarely works if there aren't any open tcp or udp ports, as the original 
poster referred there wasn't. There are tools such as hunt that exploit weak serial 
numbers so you can hijack TCP connections, but I don't believe you'll be having a lot 
of connections to or from switches or routers. The only connections usually made into 
these devices are management connections. I think in this particular case they manage 
their network devices from a serial console instead of telnet or ssh, because telnet 
or ssh wasn't open.

Then again, since NMAP can't gather good hard data from the boxes as it doesn't find 
open TCP ports, it reports a different level of TCP sequence number randomness than 
that actually encountered in real life TCP connections.

So simply put they're hardened network devices such as switches or routers that really 
won't be having security holes since they aren't offering any services. At best you 
can do denial of service against these devices, if there's a bug in the 
TCP/IP-implementation.

TONI HEINONEN, CISSP
   TELEWARE OY
   Telephone  +358 (9) 3434 9123  *  Fax  +358 (9) 3431 321
   Wireless  +358 40 836 1815
   Kauppakartanonkatu 7, 00930 Helsinki
   [EMAIL PROTECTED]  *  www.teleware.fi

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