Moderate: gnutls security update

Updated gnutls packages that fix two security issues are now available for
Red Hat Enterprise Linux 4.

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.

The GnuTLS library provides support for cryptographic algorithms and for
protocols such as Transport Layer Security (TLS).

A flaw was found in the way the TLS/SSL (Transport Layer Security/Secure
Sockets Layer) protocols handled session renegotiation. A man-in-the-middle
attacker could use this flaw to prefix arbitrary plain text to a client's
session (for example, an HTTPS connection to a website). This could force
the server to process an attacker's request as if authenticated using the
victim's credentials. This update addresses this flaw by implementing the
TLS Renegotiation Indication Extension, as defined in RFC 5746.
(CVE-2009-3555)

Refer to the following Knowledgebase article for additional details about
the CVE-2009-3555 flaw: http://kbase.redhat.com/faq/docs/DOC-20491

A flaw was found in the way GnuTLS extracted serial numbers from X.509
certificates. On 64-bit big endian platforms, this flaw could cause the
certificate revocation list (CRL) check to be bypassed; cause various
GnuTLS utilities to crash; or, possibly, execute arbitrary code.
(CVE-2010-0731)

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.

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
http://kbase.redhat.com/faq/docs/DOC-11259

533125 - CVE-2009-3555 TLS: MITM attacks via session renegotiation
573028 - CVE-2010-0731 gnutls: gnutls_x509_crt_get_serial incorrect serial decoding from ASN1 (BE64) [GNUTLS-SA-2010-1]

https://www.redhat.com/security/data/cve/CVE-2009-3555.html
https://www.redhat.com/security/data/cve/CVE-2010-0731.html
http://www.redhat.com/security/updates/classification/#moderate
http://kbase.redhat.com/faq/docs/DOC-20491