openssl security update

CentOS Errata and Security Advisory CESA-2015:1072

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.

A flaw was found in the way the TLS protocol composes the Diffie-Hellman
(DH) key exchange. A man-in-the-middle attacker could use this flaw to
force the use of weak 512 bit export-grade keys during the key exchange,
allowing them do decrypt all traffic. (CVE-2015-4000)

Note: This update forces the TLS/SSL client implementation in OpenSSL to
reject DH key sizes below 768 bits, which prevents sessions to be
downgraded to export-grade keys. Future updates may raise this limit to
1024 bits.

All openssl users are advised to upgrade to these updated packages, which
contain a backported patch to correct this issue. For the update to take
effect, all services linked to the OpenSSL library must be restarted, or
the system rebooted.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2015-June/083319.html
https://lists.centos.org/pipermail/centos-announce/2015-June/083321.html

Affected packages:
openssl
openssl-devel
openssl-libs
openssl-perl
openssl-static

Upstream details at:
https://access.redhat.com/errata/RHSA-2015:1072