I take it everyone has seen the latest advisory from ISC?

Anyone got a idea exactly where the problem is, or got an exploit?

ISC do say that an exploit isn't available, but it's been a few hours
since then :-)

Dom
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Dom De Vitto Tel. 07855 805 271
http://www.devitto.com mailto:domdevitto.com
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-----Original Message-----
From: Fyodor [mailto:fyodorinsecure.org]
Sent: Monday, November 04, 2002 6:08 PM
To: Frank Knobbe
Cc: Michael Katz; vuln-devsecurityfocus.com; d_fencegmx.net
Subject: Re: Firewall bypassing tool

On Sun, Nov 03, 2002 at 05:02:49PM -0600, Frank Knobbe wrote:
> On Fri, 2002-11-01 at 13:38, Michael Katz wrote:
> > At 11/1/2002 03:28 AM, d_fence wrote:
> >
> > One of the options for scanning is -sF, which will send SYN-FIN
> > packets. You can also use -sA, which will send SYN-ACK packets.
>
> I was about to post the same, but thought I validate first. To me it
> seemed that nmap sends a packet with the FIN flag set. I did not see
> the SYN flag set in addition to FIN, so nmap is not an answer to his
> question.

Nmap has an undocumented --scanflags option which allows you to specify
arbitrary flags using the flag names or a number. Thus a SYN-FIN scan
can be done as follows:

felix~#nmap -sS --scanflags SYNFIN -O db

Starting nmap V. 3.10ALPHA3 ( www.insecure.org/nmap/ ) Interesting ports
on db.yuma.net (192.168.0.4): (The 1601 ports scanned but not shown
below are in state: closed)
Port State Service
22/tcp open ssh
111/tcp open sunrpc
1024/tcp open kdm
Remote operating system guess: Linux Kernel 2.4.0 - 2.5.20 Uptime 58.471
days (since Fri Sep 6 23:45:12 2002)

Nmap run completed -- 1 IP address (1 host up) scanned in 10.651 seconds

Note that "-sS" causes this scan to use "SYN Scan" semantics (eg
treating SYN|ACK responses as open ports). For FIN scan semantics
(dropped packets signify open ports, RST for closed ones) just specify
"-sF" instead.

Cheers,
Fyodor

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