Vulnerability Note VU#252146

Microsoft Outlook and Microsoft Exchange TNEF decoding buffer overflow

Original Release date: 10 Jan 2006 | Last revised: 16 Jan 2006

Overview

Microsoft Outlook and Microsoft Exchange contain a buffer overflow vulnerability that may allow a remote, unauthenticated attacker to execute arbitrary code on a system running the vulnerable software.

Description

Transport Neutral Encapsulation Format (TNEF)

TNEF is a proprietary Microsoft format for encoding rich text email messages. Microsoft Outlook and Microsoft Exchange support the use of TNEF-encoded messages.

The problem

Microsoft Outlook and Microsoft Exchange do not properly validate TNEF MIME attachments, potentially allowing a buffer overflow to occur. The overflow occurs in in the process that decodes TNEF MIME attachments. A remote attacker may be able trigger the buffer overflow by sending a specially crafted TNEF MIME attachment to a vulnerable Outlook or Exchange installation.

Note that on user workstations, exploitation may require a user to open or preview a malicious mail message in Outlook. However, on Exchange servers, this vulnerability can be exploited without human interaction.

For more information, please see Microsoft Security Bulletin MS06-003.

Impact

A remote unauthenticated attacker may be able to execute arbitrary code on a system running the vulnerable software. Microsoft Outlook can trigger the vulnerability when it opens or displays a preview for a specially crafted message. Microsoft Exchange can trigger the vulnerability when it processes a specially crafted message.

Solution

Apply a patch from your vendor
Microsoft addresses this vulnerability with the updates listed in Microsoft Security Bulletin MS06-003.


Workarounds

Microsoft has listed several workarounds in Microsoft Security Bulletin MS06-003, including blocking attachments with the MIME type of application/ms-tnef.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected-10 Jan 2006
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A

References

Credit

This vulnerability was reported by Microsoft, who in turn credit John Heasman and Mark Litchfield of NGS Software.

This document was written by Will Dormann and Jeff Gennari.

Other Information

  • CVE IDs: CVE-2006-0002
  • Date Public: 10 Jan 2006
  • Date First Published: 10 Jan 2006
  • Date Last Updated: 16 Jan 2006
  • Severity Metric: 25.51
  • Document Revision: 21

Feedback

If you have feedback, comments, or additional information about this vulnerability, please send us email.