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Message-ID: <4E650AC5.8080703@fibertel.com.ar>
Date: Mon, 05 Sep 2011 14:45:41 -0300
From: root <root_@...ertel.com.ar>
To: full-disclosure@...ts.grok.org.uk
Subject: Re: Cybsec Advisory 2011 0901 Windows Script Host
DLL Hijacking
I agree, in some remote scenario this may work, but doesn't justify an
advisory.
Off-topic:
First Insect PRO, and now this?
What's happening fellow Latin-americans? our standards are falling.
Please behave, this is the Internet!
On 09/05/2011 07:33 AM, Mario Vilas wrote:
> Paul,
>
> Those file extensions correspond to scripts. If a file contains a script
> that runs when the file is double clicked, and the scripting engine is not
> sandboxed (meaning the script can do the same things an executable file can
> do) then the attack is meaningless. You can simply have the script inside
> the file do malicious things instead of planting a DLL.
>
> Binary planting, regardless of the discussion about it being a
> "vulnerability" or not, in any case only makes sense when the file only
> contains static data, or when the file contains executable code that would
> normally not have the same privileges as a standard executable file. (A
> script that doesn't get executed when double clicking on it -for example if
> a text editor is opened instead- would be the same case as in a data file).
>
> I've never used .js or .jse scripts on Windows, but all the other extensions
> are patently not sandboxed scripts. In fact, the Windows Script Host
> software is mostly used to write system maintenance scripts, so it's obvious
> its scripts can't be restricted or they'd be useless. I'm guessing the same
> applies to .js and .jse then, and of course I wouldn't mind seeing proof
> that it doesn't. However the links you provided don't really prove anything
> (the first one even says "this is not a complete list", and I admit I've
> only glanced the second one but it seems unrelated, as it applies to file
> transfers on Microsoft Sharepoint).
>
> Planting a DLL file to be executed at the same time as other executable file
> is just a convoluted way of doing the same thing. It *may* be used in some
> strange, artificial situations, but I'm not convinced there aren't better
> ways to do it, and in any case it doesn't justify an advisory. And judging
> from what the timeline reads, I believe Microsoft simply ignored this one.
>
> I hope my explanation helped :)
> -Mario
>
> On Mon, Sep 5, 2011 at 12:54 AM, <paul.szabo@...ney.edu.au> wrote:
>
>>> Application: wscript.exe
>>> Extensions: js, jse, vbe, vbs, wsf, wsh
>>> Library: wshesn.dll
>>
>> Many people commented that the above extensions are "executable"
>> already, so are (should be) treated with caution, or that they
>> can be trojaned directly without any DLL load shenanigans.
>>
>> However... looking at
>> http://technet.microsoft.com/en-us/library/cc288335%28office.12%29.aspx
>>
>> http://office.microsoft.com/en-us/windows-sharepoint-services-help/types-of-files-that-cannot-be-added-to-a-list-or-library-HA010100147.aspx
>> I do not see JS listed as executable, though JSE is listed.
>>
>> Looking at
>> http://msdn.microsoft.com/en-us/library/ms722429.aspx
>> I see JS (but not JSE) listed. Checking secpol.msc on my WindowsXP
>> machine, none of the above extensions are "designated".
>>
>> Maybe DLL hijacking is useful for some of these file types, after all?
>>
>> Cheers, Paul
>>
>> Paul Szabo psz@...hs.usyd.edu.au http://www.maths.usyd.edu.au/u/psz/
>> School of Mathematics and Statistics University of Sydney Australia
>>
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>
>
>
>
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