Topic

Updated openssl 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 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

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 the Datagram Transport Layer Security (DTLS)
protocol implementation in OpenSSL leaked timing information when
performing certain operations. A remote attacker could possibly use this
flaw to retrieve plain text from the encrypted packets by using a DTLS
server as a padding oracle. (CVE-2011-4108)

A double free flaw was discovered in the policy checking code in OpenSSL.
A remote attacker could use this flaw to crash an application that uses
OpenSSL by providing an X.509 certificate that has specially-crafted
policy extension data. (CVE-2011-4109)

An information leak flaw was found in the SSL 3.0 protocol implementation
in OpenSSL. Incorrect initialization of SSL record padding bytes could
cause an SSL client or server to send a limited amount of possibly
sensitive data to its SSL peer via the encrypted connection.
(CVE-2011-4576)

It was discovered that OpenSSL did not limit the number of TLS/SSL
handshake restarts required to support Server Gated Cryptography. A remote
attacker could use this flaw to make a TLS/SSL server using OpenSSL consume
an excessive amount of CPU by continuously restarting the handshake.
(CVE-2011-4619)

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.

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/kb/docs/DOC-11259

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 - 771770 - CVE-2011-4108 openssl: DTLS plaintext recovery attack
• BZ - 771771 - CVE-2011-4109 openssl: double-free in policy checks
• BZ - 771775 - CVE-2011-4576 openssl: uninitialized SSL 3.0 padding
• BZ - 771780 - CVE-2011-4619 openssl: SGC restart DoS attack

CVEs

• CVE-2011-4576
• CVE-2011-4108
• CVE-2011-4109
• CVE-2011-4619

References

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