Apple OfficeImport Framework Excel Memory Corruption Vulnerability
17 May. 2011
Summary
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.
Vulnerable Systems:
* iPod Touch IOS 3.1.3
* iPad IOS 3.2.2
* Mac OS X versions 10.6 through 10.6.6
* Mac OS X Server versions 10.6 through 10.6.6
The vulnerability occurs when parsing an Excel file with a certain maliciously constructed record. This record is used to describe a formula that is shared between multiple cells. In this record, the 'formula' field is used to specify the formula used. By corrupting certain opcodes within this formula it is possible to trigger a memory corruption vulnerability. This can lead to the execution of arbitrary code.
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.
