RHSA-2012:0428 - Security Advisory

Topic

Updated gnutls packages that fix three 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). GnuTLS includes libtasn1,
a library developed for ASN.1 (Abstract Syntax Notation One) structures
management that includes DER (Distinguished Encoding Rules) encoding and
decoding.

A flaw was found in the way GnuTLS decrypted malformed TLS records. This
could cause a TLS/SSL client or server to crash when processing a
specially-crafted TLS record from a remote TLS/SSL connection peer.
(CVE-2012-1573)

A flaw was found in the way libtasn1 decoded DER data. An attacker could
create a carefully-crafted X.509 certificate that, when parsed by an
application that uses GnuTLS, could cause the application to crash.
(CVE-2012-1569)

A boundary error was found in the gnutls_session_get_data() function. A
malicious TLS/SSL server could use this flaw to crash a TLS/SSL client or,
possibly, execute arbitrary code as the client, if the client passed a
fixed-sized buffer to gnutls_session_get_data() before checking the real
size of the session data provided by the server. (CVE-2011-4128)

Red Hat would like to thank Matthew Hall of Mu Dynamics for reporting
CVE-2012-1573 and CVE-2012-1569.

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

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/knowledge/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 - 752308 - CVE-2011-4128 gnutls: buffer overflow in gnutls_session_get_data() (GNUTLS-SA-2011-2)
• BZ - 804920 - CVE-2012-1569 libtasn1: DER decoding buffer overflow (GNUTLS-SA-2012-3, MU-201202-02)
• BZ - 805432 - CVE-2012-1573 gnutls: TLS record handling issue (GNUTLS-SA-2012-2, MU-201202-01)

CVEs

• CVE-2012-1569
• CVE-2011-4128
• CVE-2012-1573

References

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