OSEC

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Bugtraq archives for 1st quarter (Jan-Mar) 1999: Re: Possible security hole

Re: Possible security hole

Ryan Russell (Ryan.RussellSYBASE.COM)
Sun, 28 Mar 1999 19:07:57 -0800

>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