RHSA-2010:0167 - Security Advisory

Topic

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.

Description

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.

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

Affected Products

• Red Hat Enterprise Linux Server 4 x86_64
• Red Hat Enterprise Linux Server 4 ia64
• Red Hat Enterprise Linux Server 4 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 4.8 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 4.8 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 4.8 i386
• Red Hat Enterprise Linux Workstation 4 x86_64
• Red Hat Enterprise Linux Workstation 4 ia64
• Red Hat Enterprise Linux Workstation 4 i386
• Red Hat Enterprise Linux Desktop 4 x86_64
• Red Hat Enterprise Linux Desktop 4 i386
• Red Hat Enterprise Linux for IBM z Systems 4 s390x
• Red Hat Enterprise Linux for IBM z Systems 4 s390
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 4.8 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 4.8 s390
• Red Hat Enterprise Linux for Power, big endian 4 ppc
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 4.8 ppc

Fixes

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

CVEs

• CVE-2009-3555
• CVE-2010-0731

References

• http://www.redhat.com/security/updates/classification/#moderate
• http://kbase.redhat.com/faq/docs/DOC-20491