RHSA-2016:0306-01 -- Redhat openssl
|ID: oval:org.secpod.oval:def:502153||Date: (C)2017-10-25 (M)2018-02-19|
|Class: PATCH||Family: unix|
OpenSSL is a toolkit that implements the Secure Sockets Layer and Transport Layer Security protocols, as well as a full-strength, general purpose cryptography library. A padding oracle flaw was found in the Secure Sockets Layer version 2.0 protocol. An attacker can potentially use this flaw to decrypt RSA-encrypted cipher text from a connection using a newer SSL/TLS protocol version, allowing them to decrypt such connections. This cross-protocol attack is publicly referred to as DROWN. Note: This issue was addressed by disabling the SSLv2 protocol by default when using the "SSLv23" connection methods, and removing support for weak SSLv2 cipher suites. It is possible to re-enable the SSLv2 protocol in the "SSLv23" connection methods by default by setting the OPENSSL_ENABLE_SSL2 environment variable before starting an application that needs to have SSLv2 enabled. For more information, refer to the knowledge base article linked to in the References section. It was discovered that the SSLv2 servers using OpenSSL accepted SSLv2 connection handshakes that indicated non-zero clear key length for non-export cipher suites. An attacker could use this flaw to decrypt recorded SSLv2 sessions with the server by using it as a decryption oracle. It was discovered that the SSLv2 protocol implementation in OpenSSL did not properly implement the Bleichenbacher protection for export cipher suites. An attacker could use a SSLv2 server using OpenSSL as a Bleichenbacher oracle. Note: The CVE-2016-0703 and CVE-2016-0704 issues could allow for more efficient exploitation of the CVE-2016-0800 issue via the DROWN attack. A denial of service flaw was found in the way OpenSSL handled SSLv2 handshake messages. A remote attacker could use this flaw to cause a TLS/SSL server using OpenSSL to exit on a failed assertion if it had both the SSLv2 protocol and EXPORT-grade cipher suites enabled. A flaw was found in the way malicious SSLv2 clients could negotiate SSLv2 ciphers that have been disabled on the server. This could result in weak SSLv2 ciphers being used for SSLv2 connections, making them vulnerable to man-in-the-middle attacks. Red Hat would like to thank the OpenSSL project for reporting these issues. Upstream acknowledges Nimrod Aviram and Sebastian Schinzel as the original reporters of CVE-2016-0800 and CVE-2015-3197; David Adrian and J. Alex Halderman as the original reporters of CVE-2016-0703 and CVE-2016-0704; and Sean Burford and Emilia Kasper as the original reporters of CVE-2015-0293. All openssl users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. For the update to take effect, all services linked to the OpenSSL library must be restarted, or the system rebooted.
|Red Hat Enterprise Linux 4|