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TUCoPS :: Linux :: Conectiva :: hack3589.htm
gnupg vulnerability

[CLA-2003:798] Conectiva Security Announcement - gnupg -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 - -------------------------------------------------------------------------- CONECTIVA LINUX SECURITY ANNOUNCEMENT - -------------------------------------------------------------------------- PACKAGE : gnupg SUMMARY : GnuPG's ElGamal signing keys vulnerability DATE : 2003-12-09 16:21:00 ID : CLA-2003:798 RELEVANT RELEASES : 8, 9 - ------------------------------------------------------------------------- DESCRIPTION GnuPG[1] is an OpenPGP-compliant tool for secure communication used to, for example, sign emails, encrypt, decrypt and verify (signed) data. Phong Nguyen discovered[2] a vulnerability (CAN-2003-0971[3]) in the way GnuPG deals with type 20 ElGamal sign+encrypt keys which allows an attacker to recover the corresponding private key from a signature. Other keys, such as ElGamal type 16 used only for encryption, are not affected. This is a serious vulnerability with immediate impact: all ElGamal type 20 keys should be revoked and considered to be compromised, as well as data signed or encrypted with such a key. Please note that: - by default, GnuPG does not generate this type of key; - in order to create an ElGamal type 20 key, one must (in recent versions of GnuPG) add the --expert command line option, and even then a warning is given saying that this key should not be used. In older versions, only the warning is given. To identify the vulnerable type 20 ElGamal keys, look for the "G" identifier in a key listing such as the example below: pub 2048G/xxxxxxxx 2001-01-05 John Doe Other keys (including the ones identified by "g", lower case) are not affected. The packages provided with this update have a patch[4] created by David Shaw which disables the creation of these keys and no longer allows them to be used to create signatures. SOLUTION It is recommended that all GnuPG users upgrade their packages. Additionally, users who have ever created ElGamal type 20 sign+encrypt keys should revoke them and consider them to be compromised, as well as data signed or encrypted with such a key. REFERENCES 1.http://www.gnupg.org/ 2.http://lists.gnupg.org/pipermail/gnupg-announce/2003q4/000276.html 3.http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0971 4.http://lists.gnupg.org/pipermail/gnupg-announce/2003q4/000277.html UPDATED PACKAGES ftp://atualizacoes.conectiva.com.br/8/SRPMS/gnupg-1.0.7-1U80_3cl.sr c.rpm ftp://atualizacoes.conectiva.com.br/8/RPMS/gnupg-1.0.7-1U80_3cl.i38 6.rpm ftp://atualizacoes.conectiva.com.br/8/RPMS/gnupg-doc-1.0.7-1U80_3c l.i386.rpm ftp://atualizacoes.conectiva.com.br/9/SRPMS/gnupg-1.2.3-19780U90_ 1cl.src.rpm ftp://atualizacoes.conectiva.com.br/9/RPMS/gnupg-1.2.3-19780U90_1c l.i386.rpm ftp://atualizacoes.conectiva.com.br/9/RPMS/gnupg-doc-1.2.3-19780U9 0_1cl.i386.rpm ftp://atualizacoes.conectiva.com.br/9/RPMS/gnupg-keyserver-plugins- 1.2.3-19780U90_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/1hMO42jd0JmAcZARArapAKCITgdu6iwtmvuH7vLeYee1wz8PeACfePdk p5VHlQzYEx0okEAR6B3duWE= =mqpi -----END PGP SIGNATURE-----