RE: WMF Vunrability
- From: "Thor \(Hammer of God\)" <thor@xxxxxxxxxxxxxxx>
- To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
- Date: Wed, 4 Jan 2006 18:32:17 -0800
So we have to configure this for every HTTP rule individually?
t
-----
"I may disapprove of what you say,
but I will defend to the death your
right to say it."
----- Original Message -----
From: "Jim Harrison" <Jim@xxxxxxxxxxxx>
To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
Sent: Wednesday, January 04, 2006 5:57 PM
Subject: [isalist] RE: WMF Vunrability
http://www.ISAserver.org
Updated:
HTTP filter settings (you all know how to get there).
1. Extensions:
<choice>
Set "block specified"
Add .emf
Description="application/x-msmetafile"
Add .wmf
Description="application/x-msmetafile"
</choice>
<choice>
Set "allow specified"
Remove .emf
Remove .wmf
</choice>
<notachoice>
Set "allow all"
</notachoice>
2. Signatures:
Name=WMF-1
Description="request file type trigger"
Type="Request URL"
Signature=".emf"
Name=WMF-2
Description="request file type trigger"
Type="Request URL"
Signature=".wmf"
Name=WMF-3
Description="response headers trigger"
Type="Response Headers"
HTTP Header="content-type"
Signature="msmetafile"
Name=WMF-4
Description="response body file type trigger"
Type="Response Body"
Signature=".emf"
Name=WMF-5
Description="response body file type trigger"
Type="Response Body"
Signature=".wmf"
Name=WMF-6
Description="response body file header trigger"
Type="Response Body"
Signature="184Gmg"
WMF-6 is the kewl one because all binary files are base-64 encoded when
transferred over HTTP and FTP.
WMF files usually incorporate a predefined header value that resolves to the
Base-64 signature in this definition.
It's probably the same technique as the GFI filter, except not as smart.
-------------------------------------------------------
Jim Harrison
MCP(NT4, W2K), A+, Network+, PCG
http://isaserver.org/Jim_Harrison/
http://isatools.org
Read the help / books / articles!
-------------------------------------------------------
-----Original Message-----
From: Jim Harrison [mailto:Jim@xxxxxxxxxxxx]
Sent: Wednesday, January 04, 2006 16:03
To: [ISAserver.org Discussion List]
Subject: [isalist] RE: WMF Vunrability
http://www.ISAserver.org
HTTP filter settings (you all know how to get there).
1. Extensions:
<choice>
Set "block specified"
Add .emf
Description="application/x-msmetafile"
Add .wmf
Description="application/x-msmetafile"
</choice>
<choice>
Set "allow specified"
Remove .emf
Remove .wmf
</choice>
<notachoice>
Set "allow all"
</notachoice>
2. Signatures:
Name=WMF-1
Description="request file type trigger"
Type="Request URL"
Signature=".emf"
Name=WMF-2
Description="request file type trigger"
Type="Request URL"
Signature=".wmf"
Name=WMF-3
Description="response headers trigger"
Type="Response Headers"
HTTP Header="content-type"
Signature="msmetafile"
Name=WMF-4
Description="response body file type trigger"
Type="Response Body"
Signature=".emf"
Name=WMF-5
Description="response body file type trigger"
Type="Response Body"
Signature=".wmf"
Name=WMF-6
Description="response body file header trigger"
Type="Response Body"
Signature="184Gmg"
WMF-6 is the kewl one because all binary files are base-64 encoded when
transferred over HTTP and FTP.
WMF files usually incorporate a predefined header value that resolves to the
Base-64 signature in this definition.
It's probably the same technique as the GFI filter, except not as smart.
-------------------------------------------------------
Jim Harrison
MCP(NT4, W2K), A+, Network+, PCG
http://isaserver.org/Jim_Harrison/
http://isatools.org
Read the help / books / articles!
-------------------------------------------------------
-----Original Message-----
From: Thomas W Shinder [mailto:tshinder@xxxxxxxxxxx]
Sent: Wednesday, January 04, 2006 15:27
To: [ISAserver.org Discussion List]
Subject: [isalist] RE: WMF Vunrability
http://www.ISAserver.org
Hey Jim,
Forget about the automation, just let us know what to do :)
Thanks!
Tom
Thomas W Shinder, M.D.
Site: www.isaserver.org
Blog: http://spaces.msn.com/members/drisa/
Book: http://tinyurl.com/3xqb7
MVP -- ISA Firewalls
-----Original Message-----
From: Jim Harrison [mailto:Jim@xxxxxxxxxxxx]
Sent: Wednesday, January 04, 2006 2:18 PM
To: [ISAserver.org Discussion List]
Subject: [isalist] RE: WMF Vunrability
http://www.ISAserver.org
Sorry - I haven't.
I'm working with MSRC to narrow down the definitions and automation
for the ISA 2004 blocker.
-------------------------------------------------------
Jim Harrison
MCP(NT4, W2K), A+, Network+, PCG
http://isaserver.org/Jim_Harrison/
http://isatools.org
Read the help / books / articles!
-------------------------------------------------------
-----Original Message-----
From: Thor (Hammer of God) [mailto:thor@xxxxxxxxxxxxxxx]
Sent: Wednesday, January 04, 2006 11:45
To: [ISAserver.org Discussion List]
Subject: [isalist] RE: WMF Vunrability
http://www.ISAserver.org
Jim, did you read this? I'm wondering if the method described to
"block extensions" is correct or not. Rather than using "Configure
HTTP" and setting allowable extensions, I though one should explicitly
create a deny rule specifying both the .wmf extension *as well* as
application/x-msmetafile as the MIME type. Incoming HTTP file
associations are handled by MIME type, not file extension. Only when
there is no MIME type handed down by the server is a file extension
used (or when you do an actual file transfer, like with FTP.)
Comments on that?
t
-----
"I may disapprove of what you say,
but I will defend to the death your
right to say it."
----- Original Message -----
From: "Stefaan Pouseele" <stefaan.pouseele@xxxxxxxxx>
To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
Sent: Wednesday, January 04, 2006 11:24 AM
Subject: [isalist] RE: WMF Vunrability
> http://www.ISAserver.org
>
> Hey guys,
>
> Check out
>
http://blogs.technet.com/jesper_johansson/archive/2006/01/02/4
16762.aspx
> too
> ;-)
>
> HTH,
> Stefaan
>
> -----Original Message-----
> From: Thomas W Shinder [mailto:tshinder@xxxxxxxxxxx]
> Sent: woensdag 4 januari 2006 20:16
> To: [ISAserver.org Discussion List]
> Subject: [isalist] RE: WMF Vunrability
>
> http://www.ISAserver.org
>
> Hi Tim,
>
> I agree. There seems to be than the ususal amount of FUD
associated with
> this problem. :(
>
> Tom
>
> Thomas W Shinder, M.D.
> Site: www.isaserver.org
> Blog: http://spaces.msn.com/members/drisa/
> Book: http://tinyurl.com/3xqb7
> MVP -- ISA Firewalls
> **Who is John Galt?**
>
>
>
>> -----Original Message-----
>> From: Thor (Hammer of God) [mailto:thor@xxxxxxxxxxxxxxx]
>> Sent: Wednesday, January 04, 2006 1:01 PM
>> To: [ISAserver.org Discussion List]
>> Subject: [isalist] RE: WMF Vunrability
>>
>> http://www.ISAserver.org
>>
>> I wouldn't call it "program like behavior." They just contain both
>> metadata and rendering data in the same file (as I understand it.)
>>
>> Renaming the file to something like ".gif" or ".jpg" could
still cause
>> execution if loaded from a file, but only if the Picture and Fax
>> Viewer was the default program for those file types. From
a browser,
>> for WP&FV to open it and parse the data, it has to be that
MIME type
>> (again, as I understand
>> it.)
>>
>> While I've read here that the "way to do it" is how GFI
does it, I've
>> still not seen any information on why simple content
filtering won't
>> work. But then again, I read where Jim is working with
MSRC to come
>> up with a "workable" filter. It would be nice to get some
>> authoritative, detailed information on why MIME and file type
>> filtering *won't* work.
>>
>> t
>>
>>
>> -----
>> "I may disapprove of what you say,
>> but I will defend to the death your right to say it."
>>
>>
>> ----- Original Message -----
>> From: "Thomas W Shinder" <tshinder@xxxxxxxxxxx>
>> To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
>> Sent: Wednesday, January 04, 2006 10:31 AM
>> Subject: [isalist] RE: WMF Vunrability
>>
>>
>> http://www.ISAserver.org
>>
>> Hi Tim,
>>
>> Don't know about that, but it's a good question. But I
have to wonder
>> about other apps that open the WMF files. FWIU, WMF files
have some
>> program like behavior that allow it to call other programs if
>> something doesn't work.
>>
>> How's that as a erudite description for a process? :)
>>
>> Tom
>>
>> Thomas W Shinder, M.D.
>> Site: www.isaserver.org
>> Blog: http://spaces.msn.com/members/drisa/
>> Book: http://tinyurl.com/3xqb7
>> MVP -- ISA Firewalls
>> **Who is John Galt?**
>>
>>
>>
>> > -----Original Message-----
>> > From: Thor (Hammer of God) [mailto:thor@xxxxxxxxxxxxxxx]
>> > Sent: Wednesday, January 04, 2006 12:13 PM
>> > To: [ISAserver.org Discussion List]
>> > Subject: [isalist] RE: WMF Vunrability
>> >
>> > http://www.ISAserver.org
>> >
>> > But if he sets a differnt mime type, Fax Viewer won't open the
>> > program, right?
>> >
>> > t
>> > -----
>> > "I may disapprove of what you say, but I will defend to the death
>> > your right to say it."
>> >
>> >
>> > ----- Original Message -----
>> > From: "Thomas W Shinder" <tshinder@xxxxxxxxxxx>
>> > To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
>> > Sent: Wednesday, January 04, 2006 9:32 AM
>> > Subject: [isalist] RE: WMF Vunrability
>> >
>> >
>> > http://www.ISAserver.org
>> >
>> > Hi Jonathon,
>> >
>> > That won't work, because the scumbag can use any file
name he wants.
>> > Same goes with the MIME type. The MIME type is set at the Web
>> > server, so the scumbag can associate any MIME type he wants.
>> >
>> > Tom
>> >
>> > Thomas W Shinder, M.D.
>> > Site: www.isaserver.org
>> > Blog: http://spaces.msn.com/members/drisa/
>> > Book: http://tinyurl.com/3xqb7
>> > MVP -- ISA Firewalls
>> > **Who is John Galt?**
>> >
>> >
>> >
>> > > -----Original Message-----
>> > > From: Jonathon J. Howey [mailto:Jonathon@xxxxxxx]
>> > > Sent: Wednesday, January 04, 2006 11:25 AM
>> > > To: [ISAserver.org Discussion List]
>> > > Subject: [isalist] RE: WMF Vunrability
>> > >
>> > > http://www.ISAserver.org
>> > >
>> > > What I did to block it was:
>> > >
>> > > Internet Access Policy -> Protocols tab -> Filtering ->
>> > Configure HTTP
>> > > -> Extensions tab. Should be self explanatory from there.
>> > >
>> > >
>> > >
>> > > Jonathon J. Howey
>> > > KPSA Compliance Management Inc.
>> > > P 780.409.5620
>> > > F 780.409.5621
>> > > D 780.409.5628
>> > > C 780.965.8363
>> > > Jonathon@xxxxxxx
>> > >
>> > > Guiding the Future of Transportation www.KPSA.ca
>> > >
>> > >
>> > >
>> > > -----Original Message-----
>> > > From: Jim Harrison [mailto:Jim@xxxxxxxxxxxx]
>> > > Sent: January 4, 2006 10:12 AM
>> > > To: [ISAserver.org Discussion List]
>> > > Subject: [isalist] RE: WMF Vunrability
>> > >
>> > > http://www.ISAserver.org
>> > >
>> > > He never stated what his "block" was.
>> > >
>> > >
>> > > -------------------------------------------------------
>> > > Jim Harrison
>> > > MCP(NT4, W2K), A+, Network+, PCG
>> > > http://isaserver.org/Jim_Harrison/
>> > > http://isatools.org
>> > > Read the help / books / articles!
>> > > -------------------------------------------------------
>> > >
>> > >
>> > > -----Original Message-----
>> > > From: Brian Boyes [mailto:BrianB@xxxxxxxxx]
>> > > Sent: Wednesday, January 04, 2006 09:02
>> > > To: [ISAserver.org Discussion List]
>> > > Subject: [isalist] RE: WMF Vunrability
>> > >
>> > > http://www.ISAserver.org
>> > >
>> > > > I have installed the "wmf" block to my ISA 2004 clients but
>> > > I not sure
>> > >
>> > > > how to set this up for ISA 2000.
>> > > > Could someone provide advice of the best way to do this.
>> > >
>> > > Did anyone ever post an answer? I'm curious about this
>> "wmf block".
>> > >
>> > > Brian
>> > >
>
>
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