funsec mailing list archives

Re: Ilfak's WMF patch v. Microsoft's solution


From: Aviram Jenik <aviram () beyondsecurity com>
Date: Mon, 2 Jan 2006 15:51:22 +0200

CID is only about the location of the image. AFAIK it was never about image 
format.

When you write in an HTML code:

<IMG SRC="http://www.example.com/image.gif";> 

the image is pulled from the remote server. But when you write:
<IMG SRC="CID:image.gif"> 

Outlook/OE know to look for the image called "image.gif" in the attachments in 
the current message. When you write an HTML message in outlook and add 
images, the CID should be added automatically.

If you want to test this, take a vulnerable WMF and construct an HTML message 
that has this image embedded. Then send it to yourself, and report what 
happened. I don't have an Outlook anywhere near me or I'll do it myself.

-- 
Aviram Jenik
CEO, Beyond Security
(703) 286-7725 x104

http://www.BeyondSecurity.com
http://www.SecuriTeam.com

On Monday, 2 January 2006 15:28, Larry Seltzer wrote:
My refernce for a CID spec is for CID URLs, not the format of the target.
Oops.

Larry Seltzer
eWEEK.com Security Center Editor
http://security.eweek.com/
http://blog.ziffdavis.com/seltzer
Contributing Editor, PC Magazine
larryseltzer () ziffdavis com

-----Original Message-----
From: funsec-bounces () linuxbox org [mailto:funsec-bounces () linuxbox org] On
Behalf Of Richard M. Smith
Sent: Monday, January 02, 2006 8:19 AM
To: funsec () linuxbox org
Subject: RE: [funsec] Ilfak's WMF patch v. Microsoft's solution

I wish I knew how to build an email message with IFRAME and the CID:
protocol.  It don't feel conformtable assuming this trick wouldn't work.

BTW, I discovered that there are different types of .WMF files.  Certain
.WMF files are displayed by IE directly and do not fire up the Windows
Picture/FAX viewer when they are referenced by an IFRAME.

Richard

-----Original Message-----
From: Larry Seltzer [mailto:larry () larryseltzer com]
Sent: Monday, January 02, 2006 7:58 AM
To: 'Richard M. Smith'; funsec () linuxbox org
Subject: RE: [funsec] Ilfak's WMF patch v. Microsoft's solution


You're also presuming that the format and implementations of CID: support
WMFs. The fact that we haven't seen one so far makes me wonder if this is
the case.

I think the CID format is described here:
http://www.rfc-editor.org/rfc/rfc2111.txt and there is more useful info
here: http://mailformat.dan.info/body/html.html

Larry Seltzer
eWEEK.com Security Center Editor
http://security.eweek.com/
http://blog.ziffdavis.com/seltzer
Contributing Editor, PC Magazine
larryseltzer () ziffdavis com

-----Original Message-----
From: funsec-bounces () linuxbox org [mailto:funsec-bounces () linuxbox org] On
Behalf Of Richard M. Smith
Sent: Monday, January 02, 2006 7:27 AM
To: funsec () linuxbox org
Subject: RE: [funsec] Ilfak's WMF patch v. Microsoft's solution

I believe that it is possible that all versions of Outlook and Outlook
Express will render an IFRAME in HTML email messages if the IFRAME uses the
CID: protocol to reference an attached file.  IFRAMEs will work in this
situation  regardless of security settings.  I know for example that
Outlook 2003 never blocks images loaded with the CID: protocol in HTML
email messages.

If my theory is correct, then it should be possible to build a worm that
auto-executes simply by reading an HTML email message.  The worm also would
not require an external Web site to operate.

I asked Microsoft about the IFRAME/CID: issue on Friday.  They haven't said
yet if this is a problem or not.  I don't have any good way to test it
myself.

Richard

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_______________________________________________
Fun and Misc security discussion for OT posts.
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Note: funsec is a public and open mailing list.

_______________________________________________
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https://linuxbox.org/cgi-bin/mailman/listinfo/funsec
Note: funsec is a public and open mailing list.


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