Public Vulnerability Reports

Opera Software Opera Web Browser BitTorrent Dangling Pointer Vulnerability

07.19.07

BACKGROUND

Opera is a cross-platform web browser. More information is available at http://www.opera.com/

DESCRIPTION

Remote exploitation of a dangling pointer vulnerability in Opera Software ASA's Opera web browser could allow an attacker to execute arbitrary code with the privileges of the logged in user.

Opera 9.2 supports BitTorrent downloads. When parsing a specially crafted BitTorrent header, Opera uses memory that has already been freed. This can result in an invalid object pointer being dereferenced, and may allow for the execution of arbitrary code. The vulnerability is triggered when the user right clicks on the transfer and removes it.

ANALYSIS

Exploitation of this vulnerability allows an attacker to execute arbitrary code on the affected host with the privileges of the logged in user.

The attacker must persuade a vulnerable user into clicking a link to a BitTorrent file. The targeted user must subsequently remove the entry from the download pane. The requirement to remove the torrent is not considered to be a mitigating factor since it is natural for a user to attempt to do so when a transfer is not progressing.

DETECTION

iDefense has confirmed the existence of this vulnerability in Opera version 9.21 on Windows. Previous versions may also be affected.

WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VENDOR RESPONSE

Version 9.22 of Opera has been released to address this issue. More information can be found at the following URL.

http://www.opera.com/support/search/view/862/

CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet.

DISCLOSURE TIMELINE

06/06/2007 Initial vendor notification
06/06/2007 Initial vendor response
07/19/2007 Coordinated public disclosure

CREDIT

This vulnerability was reported to iDefense by enhalos.

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LEGAL NOTICES

Copyright © 2007 Verisign, Inc.

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