RHSA-2010:0162

Problem Description:

Updated openssl packages that fix several 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.

2. Relevant releases/architectures:

RHEL Desktop Workstation (v. 5 client) - i386, x86_64
Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64
Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64

3. Description:

OpenSSL is a toolkit that implements the Secure Sockets Layer (SSL v2/v3)
and Transport Layer Security (TLS v1) protocols, as well as a
full-strength, general purpose cryptography library.

It was discovered that OpenSSL did not always check the return value of the
bn_wexpand() function. An attacker able to trigger a memory allocation
failure in that function could cause an application using the OpenSSL
library to crash or, possibly, execute arbitrary code. (CVE-2009-3245)

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 missing return value check flaw was discovered in OpenSSL, that could
possibly cause OpenSSL to call a Kerberos library function with invalid
arguments, resulting in a NULL pointer dereference crash in the MIT
Kerberos library. In certain configurations, a remote attacker could use
this flaw to crash a TLS/SSL server using OpenSSL by requesting Kerberos
cipher suites during the TLS handshake. (CVE-2010-0433)

All OpenSSL users should upgrade to these updated packages, which contain
backported patches to resolve these issues. For the update to take effect,
all services linked to the OpenSSL library must be restarted, or the system
rebooted.

4. 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

5. Bugs fixed (http://bugzilla.redhat.com/):

533125 - CVE-2009-3555 TLS: MITM attacks via session renegotiation
567711 - Nessus PCI scan segfaults openssl dependent products due to kerberos enabled in openssl
569774 - CVE-2010-0433 openssl: crash caused by a missing krb5_sname_to_principal() return value check
570924 - CVE-2009-3245 openssl: missing bn_wexpand return value checks