RHSA-2013:1458 - Security Advisory

Topic

An updated gnupg package that fixes multiple security issues is now
available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having moderate
security impact. Common Vulnerability Scoring System (CVSS) base scores,
which give detailed severity ratings, are available for each vulnerability
from the CVE links in the References section.

Description

The GNU Privacy Guard (GnuPG or GPG) is a tool for encrypting data and
creating digital signatures, compliant with the proposed OpenPGP Internet
standard and the S/MIME standard.

It was found that GnuPG was vulnerable to the Yarom/Falkner flush+reload
cache side-channel attack on the RSA secret exponent. An attacker able to
execute a process on the logical CPU that shared the L3 cache with the
GnuPG process (such as a different local user or a user of a KVM guest
running on the same host with the kernel same-page merging functionality
enabled) could possibly use this flaw to obtain portions of the RSA secret
key. (CVE-2013-4242)

A denial of service flaw was found in the way GnuPG parsed certain
compressed OpenPGP packets. An attacker could use this flaw to send
specially crafted input data to GnuPG, making GnuPG enter an infinite loop
when parsing data. (CVE-2013-4402)

It was found that importing a corrupted public key into a GnuPG keyring
database corrupted that keyring. An attacker could use this flaw to trick a
local user into importing a specially crafted public key into their keyring
database, causing the keyring to be corrupted and preventing its further
use. (CVE-2012-6085)

It was found that GnuPG did not properly interpret the key flags in a PGP
key packet. GPG could accept a key for uses not indicated by its holder.
(CVE-2013-4351)

Red Hat would like to thank Werner Koch for reporting the CVE-2013-4402
issue. Upstream acknowledges Taylor R Campbell as the original reporter.

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

Solution

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

This update is available via the Red Hat Network. Details on how to use the
Red Hat Network to apply this update are available at
https://access.redhat.com/site/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 891142 - CVE-2012-6085 GnuPG: read_block() corrupt key input validation
• BZ - 988589 - CVE-2013-4242 GnuPG susceptible to Yarom/Falkner flush+reload cache side-channel attack
• BZ - 1010137 - CVE-2013-4351 gnupg: treats no-usage-permitted keys as all-usages-permitted
• BZ - 1015685 - CVE-2013-4402 GnuPG: infinite recursion in the compressed packet parser DoS

CVEs

• CVE-2012-6085
• CVE-2013-4351
• CVE-2013-4242
• CVE-2013-4402

References

• https://access.redhat.com/security/updates/classification/#moderate