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Ethereal fails to properly decode Transaction IDs within TCAP packets

Vulnerability Note VU#591820

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


Ethereal contains a vulnerability in the way the Transaction Capabilities Application Part (TCAP) protocol dissector parses ASN.1 encoded Transaction IDs within TCAP packets.


Ethereal is a network traffic analysis package. It includes the ability to decode packets containing TCAP data. The TCAP protocol is designed to enable advanced network telephony services between signaling points. For instance, when dialing an 800, 888, or 900 number, TCAP is used to determine the routing numbers for these digits.

According to an IETF Draft,

TCAP messages are designed for accessing databases or other switches to retrieve information or invoke features. TCAP enables the deployment of advanced intelligent network services by supporting non-circuit related information exchange between signaling points using the signaling connection control part (SCCP) connectionless service for message transport.

The Transaction ID is a reference to correlate messages\twithin the same transaction and associate the TCAP transaction with a specific application at the originating and destination signaling points.

There is a buffer overflow vulnerability in the way the TCAP protocol dissector parses ASN.1 encoded Transaction IDs within TCAP packets. Exploitation of this vulnerability could allow for arbitrary code execution.


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


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 TCAP protocol dissector by performing the following actions in Ethereal:

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

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

Vendor Information


Ethereal Affected

Updated:  March 25, 2004



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.


Please refer to the Ethereal Security Bulletin at

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

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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: 2004-03-22
Date First Published: 2004-03-25
Date Last Updated: 2004-03-25 21:14 UTC
Document Revision: 18

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