iDefense Security Advisory 10.12.11: Apple Mobile OfficeImport Framework Word Document Parsing Memory Corruption Vulnerability



iDefense Security Advisory 10.12.11
http://labs.idefense.com/intelligence/vulnerabilities/
Oct 12, 2011

I. BACKGROUND

The OfficeImport framework is an API used by Apple's mobile devices,
including the iPod Touch, iPhone, and iPad. The framework is used to
parse and display Microsoft Office file formats, such as Excel, Word,
and PowerPoint. The OfficeImport framework is used by several
applications, including MobileMail and MobileSafari. Both of these
applications are attack vectors for this vulnerability. For more
information, see the vendor's site found at the following link.

http://www.apple.com/iphone/softwareupdate/

II. DESCRIPTION

Remote exploitation of a memory corruption vulnerability in Apple Inc.'s
OfficeImport framework could allow an attacker to execute arbitrary code
with the privileges of the current user.

The vulnerability occurs when parsing a Word file with a maliciously
constructed record. Specific values within this record can trigger a
memory corruption vulnerability and result in values from the file being
used as function pointers. This allows an attacker to execute arbitrary
code.

III. ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary
code with the privileges of the user opening the file. To exploit this
vulnerability, an attacker has several attack vectors. The most
dangerous vector is through MobileSafari, which will automatically open
and parse Office files embedded in Web pages. This behavior is similar
to Microsoft Office 2000, in that it enables drive-by style attacks
without any user interaction beyond visiting a Web page (no file open
dialog is displayed, the file is simply opened). Additionally, an
attacker can e-mail a targeted user and attach a malicious file. The
user will then have to view the e-mail and attachment with MobileMail to
trigger the vulnerability.

IV. DETECTION

iOS versions prior to 5 are vulnerable.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VI. VENDOR RESPONSE

Apple has released a fix which addresses this issue. Information about
downloadable vendor updates can be found by clicking on the URLs shown.

http://lists.apple.com/archives/Security-announce/2011/Oct/msg00001.html

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2011-3260 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

10/27/2010 Initial Vendor Notification
10/27/2010 Vendor Reply
10/12/2011 Coordinated Public Disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Tobias Klein.

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X. LEGAL NOTICES

Copyright © 2011 Verisign

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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
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
this information.