BlackBerry Enterprise Server fails to properly handle Microsoft Word attachments

Overview

A buffer overflow vulnerability in BlackBerry Enterprise Server may allow a remote attacker to execute arbitrary code.

Description

A buffer overflow vulnerability exists in the BlackBerry Attachment Service component of BlackBerry Enterprise Server. This vulnerability may allow a remote attacker to execute arbitrary code when the service fails to handle a malformed Microsoft Word (.doc) document.

BlackBerry states that the following systems are vulnerable:

* BlackBerry Enterprise Server 2.2 and later for IBM Lotus Domino
* BlackBerry Enterprise Server 3.6 and later for Microsoft Exchange
* BlackBerry Enterprise Server 4.0 and later for Novell GroupWise  

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Impact

A remote attacker who can successfully convince a user to open a malicious Microsoft Word attachment on a BlackBerry Handheld device may be able to execute arbitrary code and compromise a vulnerable server.

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Solution

BlackBerry provides the following solutions:
Microsoft Exchange

* For BlackBerry Enterprise Server 3.6, Install Service Pack 7.
* For BlackBerry Enterprise Server 4.0, Install Service Pack 3, then install version 4.0 Service Pack 3 Hotfix 3.

IBM Lotus Domino

* For BlackBerry Enterprise Server 2.2, a resolution for this issue has been developed and is currently undergoing testing. A software upgrade will be made available as soon as testing is complete.
* For BlackBerry Enterprise Server 4.0, install Service Pack 3, then install version 4.0 Service Pack 3 Hotfix 4.

Novell GroupWise

* Install BlackBerry Enterprise Server 4.0 Service Pack 3, then install version 4.0 Service Pack 3 Hotfix 1.  

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Workarounds
BlackBerry provides the following workaround:

BlackBerry Enterprise Server administrators can exclude Microsoft Word (.doc) files from being processed by the Attachment Service in the BlackBerry Enterprise Server, or disable the Attachment Service completely.

To Exclude Microsoft Word (.doc) files from being processed by the Attachment Service:

1. On the desktop, click Start > Programs > BlackBerry Enterprise Server > BlackBerry Enterprise Server Configuration.
2. In the Format Extensions field, delete the .doc extension. Note: Format Extensions is an editable field that lists all the extensions that the Attachment Service will open. A colon is used as a delimiter.
3. Click Apply, then click OK.

Even though the .doc extension has been removed from the list of supported file types, the Attachment Service may automatically detect a .doc file with a renamed extension and attempt to process the file. Administrators may need to disable the Attachment Service.

To disable the Attachment Service

1. In Microsoft Windows® Administrative Tools, double-click Services.
2. Right-click BlackBerry Attachment Service, then click Stop.
3. Close the Services window.

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Vendor Information

520718

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Research in Motion (RIM) __ Affected

Updated: August 17, 2006

Status

Affected

Vendor Statement

We have not received a statement from the vendor.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

Please see BlackBerry Knowledgebase Article KB-04791

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23520718 Feedback>).

CVSS Metrics

Group	Score	Vector
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Environmental

References

• http://www.blackberry.com/knowledgecenterpublic/livelink.exe/fetch/2000/8021/8149/8052/Support_-_Corrupt_Word_file_may_cause_buffer_overflow_in_the_BlackBerry_Attachment_Service.html?nodeid=1181753&vernum=2
• <http://www.frsirt.com/english/advisories/2006/0530&gt;

Acknowledgements

This vulnerability was reported by BlackBerry.

This document was written by Katie Washok.

Other Information

CVE IDs:	CVE-2006-0761
Severity Metric:	0.59 Date Public: