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Red Hat: RHSA-2016:0306-01 Critical: OpenSSL DROWN Flaw Fix

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Calendar Grey March 1, 2016
Scroller Redhat
Vital OpenSSL security patch released for Red Hat addressing several vulnerabilities; update advised to reduce potential threats.
Updated openssl packages that fix multiple security issues are now available for Red Hat Enterprise Linux 4 Extended Lifecycle Support

Solution

Before applying this update, make sure all previously released errata relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Summary

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 padding oracle flaw was found in the Secure Sockets Layer version 2.0 (SSLv2) 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. (CVE-2016-0800)
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.(CVE-2016-0703)
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. (CVE-2016-0704)
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. (CVE-2015-0293)
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. (CVE-2015-3197)
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 (University of Michigan) and J. Alex Halderman (University of Michigan) as the original reporters of CVE-2016-0703 and CVE-2016-0704; and Sean Burford (Google) and Emilia Käsper (OpenSSL development team) 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.

References

https://access.redhat.com/security/cve/CVE-2015-0293 https://access.redhat.com/security/cve/CVE-2015-3197 https://access.redhat.com/security/cve/CVE-2016-0703 https://access.redhat.com/security/cve/CVE-2016-0704 https://access.redhat.com/security/cve/CVE-2016-0800 https://access.redhat.com/security/updates/classification#important https://access.redhat.com/articles/2176731 https://drownattack.com/ https://openssl-library.org/news/secadv/20160128.txt https://openssl-library.org/news/secadv/20160301.txt

Package List

Red Hat Enterprise Linux AS (v. 4 ELS):
Source: openssl-0.9.7a-43.23.el4.src.rpm
i386: openssl-0.9.7a-43.23.el4.i386.rpm openssl-0.9.7a-43.23.el4.i686.rpm openssl-debuginfo-0.9.7a-43.23.el4.i386.rpm openssl-debuginfo-0.9.7a-43.23.el4.i686.rpm openssl-devel-0.9.7a-43.23.el4.i386.rpm openssl-perl-0.9.7a-43.23.el4.i386.rpm
ia64: openssl-0.9.7a-43.23.el4.i686.rpm openssl-0.9.7a-43.23.el4.ia64.rpm openssl-debuginfo-0.9.7a-43.23.el4.i686.rpm openssl-debuginfo-0.9.7a-43.23.el4.ia64.rpm openssl-devel-0.9.7a-43.23.el4.ia64.rpm openssl-perl-0.9.7a-43.23.el4.ia64.rpm
x86_64: openssl-0.9.7a-43.23.el4.i686.rpm openssl-0.9.7a-43.23.el4.x86_64.rpm openssl-debuginfo-0.9.7a-43.23.el4.i386.rpm openssl-debuginfo-0.9.7a-43.23.el4.i686.rpm openssl-debuginfo-0.9.7a-43.23.el4.x86_64.rpm openssl-devel-0.9.7a-43.23.el4.i386.rpm openssl-devel-0.9.7a-43.23.el4.x86_64.rpm openssl-perl-0.9.7a-43.23.el4.x86_64.rpm
Red Hat Enterprise Linux ES (v. 4 ELS):
Source: openssl-0.9.7a-43.23.el4.src.rpm
i386: openssl-0.9.7a-43.23.el4.i386.rpm openssl-0.9.7a-43.23.el4.i686.rpm openssl-debuginfo-0.9.7a-43.23.el4.i386.rpm openssl-debuginfo-0.9.7a-43.23.el4.i686.rpm openssl-devel-0.9.7a-43.23.el4.i386.rpm openssl-perl-0.9.7a-43.23.el4.i386.rpm
x86_64: openssl-0.9.7a-43.23.el4.i686.rpm

Read the Full Advisory


Severity
important
Lowest
Low
Medium
High
Critical

Advisory ID: RHSA-2016:0306-01
Product: Red Hat Enterprise Linux
Issue date: 2016-03-01

Topic

Updated openssl packages that fix multiple security issues are nowavailable for Red Hat Enterprise Linux 4 Extended Lifecycle Support.Red Hat Product Security has rated this update as having Important securityimpact. Common Vulnerability Scoring System (CVSS) base scores, which givedetailed severity ratings, are available for each vulnerability from theCVE links in the References section.

Relevant Releases Architectures

Red Hat Enterprise Linux AS (v. 4 ELS) - i386, ia64, x86_64

Red Hat Enterprise Linux ES (v. 4 ELS) - i386, x86_64

Bugs Fixed

1202404 - CVE-2015-0293 openssl: assertion failure in SSLv2 servers1301846 - CVE-2015-3197 OpenSSL: SSLv2 doesn't block disabled ciphers1310593 - CVE-2016-0800 SSL/TLS: Cross-protocol attack on TLS using SSLv2 (DROWN)

1310811 - CVE-2016-0703 openssl: Divide-and-conquer session key recovery in SSLv2

1310814 - CVE-2016-0704 openssl: SSLv2 Bleichenbacher protection overwrites wrong bytes for export ciphers

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