OpenSSL is a toolkit that implements the Secure Sockets Layer (SSL), Transport Layer Security (TLS), and Datagram Transport Layer Security (DTLS) protocols, as well as a full-strength, general purpose cryptography library.
This update adds support for the TLS Fallback Signaling Cipher Suite Value (TLS_FALLBACK_SCSV), which can be used to prevent protocol downgrade attacks against applications which re-connect using a lower SSL/TLS protocol version when the initial connection indicating the highest supported protocol version fails.
This can prevent a forceful downgrade of the communication to SSL 3.0. The SSL 3.0 protocol was found to be vulnerable to the padding oracle attack when using block cipher suites in cipher block chaining (CBC) mode. This issue is identified as CVE-2014-3566, and also known under the alias POODLE. This SSL 3.0 protocol flaw will not be addressed in a future update; it is recommended that users configure their applications to require at least TLS protocol version 1.0 for secure communication.
For additional information about this flaw, see the Knowledgebase article at https://access.redhat.com/articles/1232123
All OpenSSL users are advised to upgrade to these updated packages, which contain a backported patch to mitigate the CVE-2014-3566 issue. For the update to take effect, all services linked to the OpenSSL library (such as httpd and other SSL-enabled services) must be restarted or the system rebooted.