[isapros] Re: FW: FWENGMON issue for the brain trust
- From: "Jim Harrison" <Jim@xxxxxxxxxxxx>
- To: <isapros@xxxxxxxxxxxxx>
- Date: Thu, 6 Jul 2006 22:11:44 -0700
I do, but Danny made me wait until I stopped spitting expletives.
I agree with message #2 - if the app isn't there, the functionality isn't
available.
Granted, the Mark Russonovich's or Tim Mullens could probably sniff out the
APIs and create all manner of H&D, but so what - anyone of that skill level
that has direct local-admin access to your box just got themselves a free
server anyway.
If the app isn't left on the box and the attacker doesn't have local-logon,
admin rights (oh damn; game over), then WTF cares what APIs may exist that you
can't get to without prior knowledge (and not-insignificant programming skills)
or a product-team-provided debugging tool? IOW, if they're all that worried
about who can do what when they log onto the ISA locally as an ISA admin,
they've already lost the war.
This guy has way too much time on his hands if this is the sort of thing he
gets wound up about. Was this Andy?
We now return you to your regularly scheduled profanity-filled retorts.
________________________________
From: isapros-bounce@xxxxxxxxxxxxx on behalf of Thomas W Shinder
Sent: Thu 7/6/2006 2:22 PM
To: isapros@xxxxxxxxxxxxx
Subject: [isapros] FW: FWENGMON issue for the brain trust
No one gots no opinion on this one?
-----Original Message-----
From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx]
On Behalf Of Thomas W Shinder
Sent: Wednesday, July 05, 2006 9:10 PM
To: isapros@xxxxxxxxxxxxx
Subject: [isapros] FWENGMON issue for the brain trust
Hey folks,
There was a discussion on the beta newsgroup that I thought would be
interesting to put in front of the brain trust. There's nothing NDA
here, so it's cool. My impression is that the person who was concerned
about the fwengmon /allow option is akin to the IPv6 issue -- if the
admin is incompetent, malicious or both, then of course the fwengmon
/all option can be abused. But the same incompetent and malicious admins
can hork any other kind of firewall.
The example of the SBSer reading e-mail on the box is archetypal
for the idiot admin who goes out of his way to subvert firewall
security, so how is this different from creating an "allow all from
everyone to everywhere" which you can do on any firewall, including the
ISA firewall?
Wondering if customers really need to get their undies in a
bunch about this or its is calling "fire" at a weenie roast?
===========================
Message 1:
In my personal opinion, the interface method which "fwengmon.exe /allow"
calls should not exist; there should be no such bypass-the-firewall
method,
even if it is handy for troubleshooting.
If it can't be removed, then there should at least be an Event Log
message
whenever it's invoked, and the fwengmon.exe tool should be able to
display
whether or not there are any bypasses currently configured so that it
can be
audited (the "/noallow" switch will turn any bypasses off, but it
doesn't
indicate whether it did anything or what the IP addresses were in the
cancelled bypass).
I'm sure the ISA development team uses the bypass feature constantly,
but
that's development/debug code, and it wouldn't have to exist when the
final
product ships. Whenever I show others the "/allow" switch and its
invisibility of operation, the response is always very negative.
Message 2:
Yes, but you have to get the file on the box. If I can place files on
the
firewall without your knowledge, the game is already over, isn't it?
Message 3:
I agree it's a bit paranoid, but I think the even greater threat comes
from
external buffer overflow attacks that call that method or malware that
does
the same when invoked by an interactively-logged on administrator who
browses the net or reads e-mail as admin while at the ISA box (which
will
probably be running SBS, yet it will be ISA that gets the blame for it
when
the vulnerability is published). In these cases, fwengmon.exe wouldn't
even
have to be on the local drive. At a minimum, it would be nice if
invoking
that method --whatever it is-- at least wrote a message to an Event Log.
(I
also don't like how "lockdown mode" does not drop all existing
connections
and still allows new outbound connections, but that's another story and
easy
enough to fix with a custom panic script.)
On a purely marketing level, too, ISA has lots of prejudice to overcome,
so
I've encountered anti-Microsoft sysadmins who jump all over this
"invisible
hole feature" to undermine ISA as a trustworthy firewall (and then this
can
sway the fence-sitters in the room to lean to the negative side). I'd
still
prefer it if this firewall-bypass functionality didn't exist at all...
======================
Thomas W Shinder, M.D.
Site: www.isaserver.org <http://www.isaserver.org/>
Blog: http://blogs.isaserver.org/shinder/
Book: http://tinyurl.com/3xqb7 <http://tinyurl.com/3xqb7>
MVP -- ISA Firewalls
All mail to and from this domain is GFI-scanned.
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