Ethereal fails to properly parse NetFlow UDP packets with an overly large template_entry count

Overview

Ethereal fails to properly parse v9_template structures in NetFlow UDP packets with an overly large template_entry count. This could allow an attacker to execute arbitrary code.

Description

Ethereal is a network traffic analysis package. It includes the ability to decode packets containing NetFlow data. There is a buffer overflow vulnerability in the way the NetFlow v9 dissector parses v9_template structures in a NetFlow UDP packet. A remote, unauthenticated attacker could exploit this vulnerability by sending a NetFlow UDP packet containing an overly large template_entry count which could allow for arbitrary code execution.

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Impact

A remote, unauthenticated attacker could execute arbitrary code on the vulnerable system.

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Solution

Upgrade

Upgrade to version 0.10.3 or later.

Note: Ethereal is considered BETA software at this time.

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Disable Dissector

If you are unable to upgrade to version 0.10.3 or later, you can disable the NetFlow protocol dissector by performing the following actions in Ethereal:

(for Ethereal versions 0.9.x)

1. Select Edit->Protocols
2. Deselect the NetFlow protocol dissector from the list

(for Ethereal versions 0.10.x)

1. Select Analyze->Enabled Protocols
2. Disable the CFLOW (Cisco NetFlow) protocol dissector from the list by unchecking its “Status” checkbox

However, it is strongly encouraged to upgrade to version 0.10.3 or later.

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Vendor Information

644886

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Ethereal __ Affected

Updated: March 24, 2004

Status

Affected

Vendor Statement

Please see the Ethereal Security Bulletin at <http://www.ethereal.com/appnotes/enpa-sa-00013.html&gt;.

Vendor Information

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

Addendum

The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23644886 Feedback>).

CVSS Metrics

Group	Score	Vector
Base
Temporal
Environmental

References

• <http://security.e-matters.de/advisories/032004.html&gt;
• <http://www.ethereal.com/appnotes/enpa-sa-00013.html&gt;
• <http://secunia.com/advisories/11185/&gt;

Acknowledgements

Ethereal credits Stefan Esser for reporting this vulnerability.

This document was written by Damon Morda.

Other Information

CVE IDs:	CVE-2004-0176
Severity Metric:	9.82 Date Public: