iDefense Security Advisory 07.28.09
http://labs.idefense.com/intelligence/vulnerabilities/ 
Jul 28, 2009

I. BACKGROUND

Microsoft's Component Object Model (COM) was designed to allow
interoperability between disjointed software components. It is a
standardized interface solution to the programming dilemmas involved in
object oriented programming, distributed transactions, and
inter-language communications. COM is involved at some level in DDE,
OLE, COM+, ActiveX, and DCOM. COM objects can be embedded in various
document formats, Web Pages, and various other media technologies.
Microsoft's Active Template Library (ATL) is a set of C++ templates
that simplify developing COM objects. More information on COM and ATL
can be found at the following URLs.

http://www.microsoft.com/com/default.mspx 

http://msdn.microsoft.com/en-us/library/t9adwcde(VS.80).aspx 

II. DESCRIPTION

Remote exploitation of an information disclosure vulnerability in
Microsoft's ATL/MFC ActiveX template, as included in various vendor's
ActiveX controls, allows attackers to read memory contents within
Internet Explorer.

One aspect of COM is a process called initialization. This process
allows a program to load and store a COM object within various
containers, such as OLE compound storage files and raw streams.

Depending upon certain characteristics of an OLE component designed with
the Microsoft ATL, it is possible to read arbitrary memory inside the
Internet Explorer process. By loading a vulnerable ActiveX control and
passing in specially crafted persistent storage data, an attacker can
cause a string to be read in without being properly NULL terminated.
After the object is initialized the attacker may read the data using
Java Script. Since the string functions rely on NULL termination to
keep track of the end of the string, the attacker may read into the
next chunk of memory continuing until two NULL bytes are encountered.

III. ANALYSIS

Exploitation of the above vulnerabilities will result in the disclosure
of memory contents, potentially including sensitive information. The
attack vectors include Internet Explorer, WordPad, Microsoft Office,
and any other program that loads arbitrary persistence data and gives
the attacker an opportunity to read back the data.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability inside
Microsoft's ATL version 9.0. Any source code compiled with these
libraries may also be vulnerable. Previous versions may also be
affected.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VI. VENDOR RESPONSE

Microsoft has released a security bulletin which addresses this issue.
For more information, consult their advisory at the following URL:

http://www.microsoft.com/technet/security/Bulletin/MS09-035.mspx 

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2009-2495 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for 
security problems.

VIII. DISCLOSURE TIMELINE

12/05/2008  Initial Contact
01/05/2009  Microsoft requested PoC
01/06/2009  iDefense sent PoC
01/23/2009  iDefense requested status update
01/26/2009  iDefense requested status update
01/27/2009  Microsoft reports status
02/09/2009  Microsoft reports status
02/26/2009  Microsoft reports status
03/27/2009  Microsoft reports status
04/23/2009  Microsoft reports status, predicts September release
05/13/2009  Microsoft reports status, predicts October release
05/21/2009  Microsoft requests conference call
06/03/2009  Conference call takes place
07/28/2009  Public disclosure via MS09-035 out-of-band bulletin
07/29/2009  Material presented at BlackHat USA

IX. CREDIT

This vulnerability was discovered by Ryan Smith of iDefense Labs.

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http://labs.idefense.com/ 

X. LEGAL NOTICES

Copyright =A9 2009 iDefense, Inc.

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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
 There are no warranties with regard to this information. Neither the
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reliance on, this information.