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."
http://www.ISAserver.org
Hey guys,
Check out
http://blogs.technet.com/jesper_johansson/archive/2006/01/02/416762.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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