5 - RHSA-2006:0266

Problem Description:

An updated GnuPG package that fixes signature verification flaws as well as minor bugs is now available.

This update has been rated as having important security impact by the Red Hat Security Response Team.

2. Relevant releases/architectures:

Red Hat Enterprise Linux AS (Advanced Server) version 2.1 - i386, ia64 Red Hat Linux Advanced Workstation 2.1 - ia64 Red Hat Enterprise Linux ES version 2.1 - i386 Red Hat Enterprise Linux WS version 2.1 - i386 Red Hat Enterprise Linux AS version 3 - i386, ia64, ppc, s390, s390x, x86_64 Red Hat Desktop version 3 - i386, x86_64 Red Hat Enterprise Linux ES version 3 - i386, ia64, x86_64 Red Hat Enterprise Linux WS version 3 - i386, ia64, x86_64 Red Hat Enterprise Linux AS version 4 - i386, ia64, ppc, s390, s390x, x86_64 Red Hat Enterprise Linux Desktop version 4 - i386, x86_64 Red Hat Enterprise Linux ES version 4 - i386, ia64, x86_64 Red Hat Enterprise Linux WS version 4 - i386, ia64, x86_64

3. Problem description:

GnuPG is a utility for encrypting data and creating digital signatures.

Tavis Ormandy discovered a bug in the way GnuPG verifies cryptographically signed data with detached signatures. It is possible for an attacker to construct a cryptographically signed message which could appear to come from a third party. When a victim processes a GnuPG message with a malformed detached signature, GnuPG ignores the malformed signature, processes and outputs the signed data, and exits with status 0, just as it would if the signature had been valid. In this case, GnuPG's exit status would not indicate that no signature verification had taken place. This issue would primarily be of concern when processing GnuPG results via an automated script. The Common Vulnerabilities and Exposures project assigned the name CVE-2006-0455 to this issue.

Tavis Ormandy also discovered a bug in the way GnuPG verifies cryptographically signed data with inline signatures. It is possible for an attacker to inject unsigned data into a signed message in such a way that when a victim processes the message to recover the data, the unsigned data is output along with the signed data, gaining the appearance of having been signed. This issue is mitigated in the GnuPG shipped with Red Hat Enterprise Linux as the --ignore-crc-error option must be passed to the gpg executable for this attack to be successful. The Common Vulnerabilities and Exposures project assigned the name CVE-2006-0049 to this issue.

Please note that neither of these issues affect the way RPM or up2date verify RPM package files, nor is RPM vulnerable to either of these issues.

All users of GnuPG are advised to upgrade to this updated package, which contains backported patches to correct these issues.

4. Solution:

Before applying this update, make sure all previously released errata relevant to your system have been applied.

This update is available via Red Hat Network. To use Red Hat Network, launch the Red Hat Update Agent with the following command:

up2date

This will start an interactive process that will result in the appropriate RPMs being upgraded on your system.

5. Bug IDs fixed (http://bugzilla.redhat.com/):

167392 - initial gpg run doesn't create .gnupg/secring.gpg 179506 - RHEL3, gnupg-1.2.1-10, gpg: Creates corrupt files (probably 2GB problem) 183484 - CVE-2006-0455 gpg will quietly exit when attempting to verify a malformed message 184556 - CVE-2006-0049 Gnupg incorrect malformed message verification