iDefense Security Advisory 06.21.10
http://labs.idefense.com/intelligence/vulnerabilities/ 
Jun 21, 2010

I. BACKGROUND

libTIFF is a free and popular image library that provides support for
displaying and manipulating Tag Image File Format (TIFF) image data.
This library is used by numerous applications and is included in
various vendor operating system distributions. For more information,
see the vendor's site found at the following link:
http://www.libtiff.org 

II. DESCRIPTION

Remote exploitation of a stack buffer overflow vulnerability in version
3.9.2 of LibTIFF, as included in various vendors' operating system
distributions, could allow an attacker to execute arbitrary code with
the privileges of the current user.

This vulnerability is due
to insufficient bounds checking when copying data into a stack allocated
buffer. During the processing of a certain EXIF tag a fixed sized stack
buffer is used as a destination location for a memory copy. This memory
copy can cause the bounds of a stack buffer to be overflown and this
condition may lead to arbitrary code execution.

III. ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary
code with the privileges of the current user. In order to exploit this
vulnerability, a user must load a web page containing a specially
crafted TIFF image. An attacker typically accomplishes this via social
engineering or injecting content into compromised, trusted sites.
Typical social engineering attacks will pass URLs as part of instant
messages or electronic mail.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in version
3.9.2 of libTIFF. Previous versions are not affected.

V. WORKAROUND

iDefense is currently unaware of any workaround for this issue.

VI. VENDOR RESPONSE

Multiple vendors have released patches to address this issue.
Information about downloadable vendor updates can be found by clicking
on the URL shown.
http://www.remotesensing.org/libtiff/v3.9.4.html#libtiff 
http://www.ubuntu.com/usn/usn-954-1 
https://bugzilla.redhat.com/show_bug.cgi?id=599576

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2010-2067 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

05/27/2010  Initial Vendor Notification
05/27/2010  Initial Vendor Reply
06/21/2010  Coordinated Public Disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Dan Rosenberg.

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X. LEGAL NOTICES

Copyright =A9 2010 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.
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