Synopsis

Important: gnutls security update

Type/Severity

Security Advisory: Important

Topic

Updated gnutls packages that fix multiple security issues are now available
for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having
Important 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 GnuTLS library provides support for cryptographic algorithms and for
protocols such as Transport Layer Security (TLS). The gnutls packages also
include the libtasn1 library, which provides Abstract Syntax Notation One
(ASN.1) parsing and structures management, and Distinguished Encoding Rules
(DER) encoding and decoding functions.

A flaw was found in the way GnuTLS parsed session IDs from ServerHello
messages of the TLS/SSL handshake. A malicious server could use this flaw
to send an excessively long session ID value, which would trigger a buffer
overflow in a connecting TLS/SSL client application using GnuTLS, causing
the client application to crash or, possibly, execute arbitrary code.
(CVE-2014-3466)

It was discovered that the asn1_get_bit_der() function of the libtasn1
library incorrectly reported the length of ASN.1-encoded data. Specially
crafted ASN.1 input could cause an application using libtasn1 to perform
an out-of-bounds access operation, causing the application to crash or,
possibly, execute arbitrary code. (CVE-2014-3468)

Multiple incorrect buffer boundary check issues were discovered in
libtasn1. Specially crafted ASN.1 input could cause an application using
libtasn1 to crash. (CVE-2014-3467)

Multiple NULL pointer dereference flaws were found in libtasn1's
asn1_read_value() function. Specially crafted ASN.1 input could cause an
application using libtasn1 to crash, if the application used the
aforementioned function in a certain way. (CVE-2014-3469)

Red Hat would like to thank GnuTLS upstream for reporting these issues.
Upstream acknowledges Joonas Kuorilehto of Codenomicon as the original
reporter of CVE-2014-3466.

Users of GnuTLS are advised to upgrade to these updated packages, which
correct these issues. For the update to take effect, all applications
linked to the GnuTLS or libtasn1 library must be restarted.

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 - 1101932 - CVE-2014-3466 gnutls: insufficient session id length check in _gnutls_read_server_hello (GNUTLS-SA-2014-3)
• BZ - 1102022 - CVE-2014-3467 libtasn1: multiple boundary check issues
• BZ - 1102323 - CVE-2014-3468 libtasn1: asn1_get_bit_der() can return negative bit length
• BZ - 1102329 - CVE-2014-3469 libtasn1: asn1_read_value_type() NULL pointer dereference

CVEs

• CVE-2014-3467
• CVE-2014-3466
• CVE-2014-3469
• CVE-2014-3468

References