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Message-ID: <441C9847.60103@heapoverflow.com>
Date: Sat Mar 18 23:31:26 2006
From: ad at heapoverflow.com (ad@...poverflow.com)
Subject: Re: Remote overflow in MSIE script
action handlers (mshtml.dll)
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here we say:
et puis 100 balles et 1 mars ? hu ;>
Manuel Moreno Leiva wrote:
> great exploit.. works fine in my workstation
> i have WinXp Sp2 IE 6.0.2900.2180.xpsp_sp2_gdr.050301-1519
> you have a exploit usable for this?
>
> Best Regards
>
> Manuel Moreno
> AsesoriaPC
> Stgo,Chile
>
> 2006/3/16, Michal Zalewski <lcamtuf@...ne.ids.pl>:
>> Good morning,
>>
>> This might not come as a surprise, but there appears to be a *very*
>> interesting and apparently very much exploitable overflow in Microsoft
>> Internet Explorer (mshtml.dll).
>>
>> This vulnerability can be triggered by specifying more than a couple
>> thousand script action handlers (such as onLoad, onMouseMove, etc) for any
>> single HTML tag. Due to a programming error, MSIE will then attempt to
>> write memory array out of bounds, at an offset corresponding to the ID of
>> the script action handler multiplied by 4 (due to 32-bit address clipping,
>> the result is a small positive integer).
>>
>> The list of IDs can be found on the Web, and is as follows (values in
>> parentheses = resulting offsets):
>>
>> onhelp = 0x8001177d (+0x45df4)
>> onclick = 0x80011778 (+0x45de0)
>> ondblclick = 0x80011779 (+0x45de4)
>> onkeyup = 0x80011776 (+0x45dd8)
>> onkeydown = 0x80011775 (+0x45dd4)
>> onkeypress = 0x80011777 (+0x45ddc)
>> onmouseup = 0x80011773 (+0x45dcc)
>> onmousedown = 0x80011772 (+0x45dc8)
>> onmousemove = 0x80011774 (+0x45dd0)
>> onmouseout = 0x80011771 (+0x45dc4)
>> onmouseover = 0x80011770 (+0x45dc0)
>> onreadystatechange = 0x80011789 (+0x45e24)
>> onafterupdate = 0x80011786 (+0x45e18)
>> onrowexit = 0x80011782 (+0x45e08)
>> onrowenter = 0x80011783 (+0x45e0c)
>> ondragstart = 0x80011793 (+0x45e4c)
>> onselectstart = 0x80011795 (+0x45e54)
>>
>> What happens next depends on the structure of the page in which the
>> malicious tag is embedded, as well as previously visited page and
>> previously initialized extensions (all these factors can be controlled by
>> the attacker).
>>
>> When the offending page contains no additional elements, and the user is
>> not redirected from elsewhere, the browser will typically crash
>> immediately, because there is no allocated memory at the resulting offset.
>> In all other cases, crashes will typically occur later, due to attempted
>> use of unrelated but corrupted in-memory buffers -for example, when the
>> user attempts to leave or reload the page. Another good example is coming
>> from a page that contains Macromedia Flash - this usually causes the Flash
>> plugin itself to choke on corrupted memory on cleanup.
>>
>> For non-believers, there's a short but fiery demonstration page available
>> at http://lcamtuf.coredump.cx/iedie.html (yes, it will probably crash your
>> browser).
>>
>> Tested on MSIE 6.0.2900.2180.xpsp2.040806-1825 on Windows XP SP2. As far
>> as I can tell, other browser makes (Firefox, Opera) are not susceptible to
>> this attack.
>>
>> I eagerly await due reprimend from Microsoft for not disclosing this
>> vulnerability in a manner that benefits them most, not passing start, not
>> collecting $200 (from iDefense?).
>>
>> Regards,
>> /mz
>> http://lcamtuf.coredump.cx/silence/
>>
>
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