Re: Possible security hole

From: Ryan Russell (Ryan.Russellat_private)
Date: Sun Mar 28 1999 - 19:07:57 PST

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    >The first 25 packets were lost before the interface's initialization. The
    >packets with sequence number greater than 34 are droped from the firewall.
    >What about the packets with sequence number 25-34? Is it possible that
    >someone can use this time (after the interface's initialization and before
    >the firewall's initialization) to do something bad?
    
    Absolutely.  There is a period of time while the FW is booting when the
    OS is up, but the FW software is not.  FW-1 makes no attempt to hook
    the IP stack in such a way to prevent this.  You MUST secure the
    underlying OS ON YOUR OWN.  FW-1 does NOT "harden" the OS..
    
    As for pings being dropped.. it's not unusual for some OSes
    (IOS included) to respond to pings, and then not, and then
    respond again during a boot.  The second time not responding
    may be when the FW software kicked it, depending on the rules
    set.
    
                             Ryan
    



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