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Carnegie Mellon University

Software Engineering Institute

CERT Coordination Center

GnuPG contains flaw in key validation code

Vulnerability Note VU#397604

Original Release Date: 2003-05-20 | Last Revised: 2003-07-14

Overview

A vulnerability in GnuPG may cause keys with multiple user ID's to give other user IDs on the key a false amount of validity.

Description

From the GnuPG homepage:

GnuPG stands for GNU Privacy Guard and is GNU's tool for secure communication and data storage. It can be used to encrypt data and to create digital signatures. It includes an advanced key management facility and is compliant with the proposed OpenPGP Internet standard as described in RFC 2440. As such, it is aimed to be compatible with PGP from NAI, Inc.
A vulnerability in GnuPG may cause keys with multiple user ID's to give other user IDs on the key a false amount of validity. From the GnuPG announcement:
As part of the development of GnuPG 1.2.2, a bug was discovered in the key validation code. This bug causes keys with more than one user ID to give all user IDs on the key the amount of validity given to the most-valid key.

Impact

A user encrypting a message using GnuPG may not be warned if the target user key being encrypted to has an "insufficient or no trust path".

Solution

Apply a patch from your vendor. If a patch is not available, you may wish to apply the patch produced by the GnuPG team.

Vendor Information

397604
 
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Conectiva Affected

Updated:  July 14, 2003

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

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

- --------------------------------------------------------------------------
CONECTIVA LINUX SECURITY ANNOUNCEMENT
- --------------------------------------------------------------------------

PACKAGE   : gnupg
SUMMARY   : GnuPG key validity vulnerability
DATE      : 2003-07-11 16:02:00
ID        : CLA-2003:694
RELEVANT
RELEASES  : 7.0, 8, 9

- -------------------------------------------------------------------------

DESCRIPTION
GnuPG[1] is a OpenPGP-compliant tool for secure communication used
to, for example, sign emails, encrypt, decrypt and verify (signed)
data.

During the development of GnuPG 1.2.2, a bug has been found in the
key validation code. This bug causes keys with more than one user ID
to give all user IDs on the key the amount of validity given to the
most-valid key. In this situation, GnuPG would not emit a warning
when a low trust ID is used for encryption if that key also contains
a trusted enough ID.

Keys with only one ID are not affected by this problem.

For Conectiva Linux 7.0 and 8, the GnuPG package has been updated to
version 1.0.7 and includes a fix provided by the authors[2]. GnuPG in
Conectiva Linux 9 does not need a version upgrade and includes the
same patch.



SOLUTION
It is recommended that all GnuPG users upgrade their packages.

IMPORTANT: as part of the changes introduced in GnuPG versions 1.0.7
and later, public keys for which the user as a corresponding secret
key are no longer automatically considered trusted. To ease the
transition, a script called "convert-from-106" (part of GnuPG-1.2.2)
has been included in these packages. If executed, this script will
mark as trusted all public keys for which the current user has the
corresponding private keys.


REFERENCES
1.http://www.gnupg.org/
2.http://lists.gnupg.org/pipermail/gnupg-announce/2003q2/000268.html
3.http://cve.mitre.org/cgi-bin/cvename.cgi?name=2003-0255


UPDATED PACKAGES
ftp://atualizacoes.conectiva.com.br/7.0/SRPMS/gnupg-1.0.7-1U70_1cl.src.rpm
ftp://atualizacoes.conectiva.com.br/7.0/RPMS/gnupg-1.0.7-1U70_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/7.0/RPMS/gnupg-doc-1.0.7-1U70_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/8/SRPMS/gnupg-1.0.7-1U80_1cl.src.rpm
ftp://atualizacoes.conectiva.com.br/8/RPMS/gnupg-1.0.7-1U80_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/8/RPMS/gnupg-doc-1.0.7-1U80_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/9/SRPMS/gnupg-1.2.1-19780U90_1cl.src.rpm
ftp://atualizacoes.conectiva.com.br/9/RPMS/gnupg-1.2.1-19780U90_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/9/RPMS/gnupg-doc-1.2.1-19780U90_1cl.i386.rpm
ftp://atualizacoes.conectiva.com.br/9/RPMS/gnupg-keyserver-plugins-1.2.1-19780U90_1cl.i386.rpm


ADDITIONAL INSTRUCTIONS
The apt tool can be used to perform RPM packages upgrades:

- run:                 apt-get update
- after that, execute: apt-get upgrade

Detailed instructions reagarding the use of apt and upgrade examples
can be found at http://distro.conectiva.com.br/atualizacoes/#apt?idioma=en

- -------------------------------------------------------------------------
All packages are signed with Conectiva's GPG key. The key and instructions
on how to import it can be found at
http://distro.conectiva.com.br/seguranca/chave/?idioma=en
Instructions on how to check the signatures of the RPM packages can be
found at http://distro.conectiva.com.br/seguranca/politica/?idioma=en

- -------------------------------------------------------------------------
All our advisories and generic update instructions can be viewed at
http://distro.conectiva.com.br/atualizacoes/?idioma=en

- -------------------------------------------------------------------------
Copyright (c) 2003 Conectiva Inc.
http://www.conectiva.com

- -------------------------------------------------------------------------
subscribe: conectiva-updates-subscribe@papaleguas.conectiva.com.br
unsubscribe: conectiva-updates-unsubscribe@papaleguas.conectiva.com.br
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: For info see http://www.gnupg.org

iD8DBQE/DxFK42jd0JmAcZARAsJ0AJ9WRo+Lzu25R0TqvmkH+ZkTFIYmdgCgvhrs
3naNkr4YyUGgYuYGJbq+u5w=
=s3ko
-----END PGP SIGNATURE-----

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

Free Software Foundation Affected

Updated:  May 20, 2003

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 http://lists.gnupg.org/pipermail/gnupg-announce/2003q2/000268.html.

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

Guardian Digital Inc. Affected

Updated:  May 20, 2003

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 http://lwn.net/Articles/32420/.

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

OpenPKG Affected

Updated:  May 20, 2003

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 http://www.openpkg.org/security/OpenPKG-SA-2003.029-gnupg.html.

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

Red Hat Inc. Affected

Updated:  May 21, 2003

Status

Affected

Vendor Statement

Please see https://rhn.redhat.com/errata/RHSA-2003-175.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.

Slackware Affected

Updated:  May 22, 2003

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 http://www.slackware.com/security/viewer.php?l=slackware-security&y=2003&m=slackware-security.296270.

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


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References

Acknowledgements

This vulnerability was discovered by the GnuPG Team. The CERT/CC thanks the GnuPG Team for providing information upon which this document is based.

This document was written by Ian A Finlay.

Other Information

CVE IDs: CVE-2003-0255
Severity Metric: 6.75
Date Public: 2003-05-03
Date First Published: 2003-05-20
Date Last Updated: 2003-07-14 18:19 UTC
Document Revision: 10

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