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Ethereal fails to properly decode BGP packets containing MPLS IPv6 labels

Vulnerability Note VU#931588

Original Release Date: 2004-03-25 | Last Revised: 2004-03-25

Overview

Ethereal contains a vulnerability in the way the Border Gateway Protocol (BGP) protocol dissector decodes Multiprotocol Label Switching (MPLS) IPv6 labels.

Description

Ethereal is a network traffic analysis package. It includes the ability to decode packets containing BGP data. According to RFC3031, an MPLS label is an identifier used to represent the Forwarding Equivalence Class (FEC) to which that packet is assigned. There is a buffer overflow vulnerability in the way the BGP protocol dissector decodes MPLS IPv6 labels.

According to the e-matters Security Advisory:
When parsing a BGP Packet with a MPLS IPv6 label up to 13 bytes on the stack may be overwritten with arbitrary data. Due to the stacklayout exploitability seems unlikly and was therefore not tested.

Impact

A remote, unauthenticated attacker could cause Ethereal to crash or potentially execute code of the attacker's choice.

Solution

Upgrade

Upgrade to version 0.10.3 or later.

Note: Ethereal is considered BETA software at this time.

Disable Dissector

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

(for Ethereal versions 0.8.x and 0.9.x)
1) Select Edit->Protocols
2) Deselect the BGP protocol dissector from the list

(for Ethereal versions 0.10.x)
1) Select Analyze->Enabled Protocols
2) Disable the BGP protocol dissector from the list by unchecking its "Status" checkbox

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

Vendor Information

931588
 
Affected   Unknown   Unaffected

Ethereal

Updated:  March 25, 2004

Status

  Vulnerable

Vendor Statement

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

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.


CVSS Metrics

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

References

Credit

Ethereal credits Stefan Esser for reporting this vulnerability.

This document was written by Damon Morda.

Other Information

CVE IDs: CVE-2004-0176
Severity Metric: 2.89
Date Public: 2004-03-22
Date First Published: 2004-03-25
Date Last Updated: 2004-03-25 16:49 UTC
Document Revision: 10

Sponsored by the Department of Homeland Security Office of Cybersecurity and Communications.