RHEL 5 : openssl (RHSA-2016:0304) (DROWN)

This script is Copyright (C) 2016-2017 Tenable Network Security, Inc.

Synopsis :

The remote Red Hat host is missing one or more security updates.

Description :

Updated openssl packages that fix multiple security issues are now
available for Red Hat Enterprise Linux 5.6 and 5.9 Long Life.

Red Hat Product Security has rated this update as having Important
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.

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.

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

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

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

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. (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 Kasper (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.

See also :


Solution :

Update the affected packages.

Risk factor :

Medium / CVSS Base Score : 5.0
CVSS Temporal Score : 3.7
Public Exploit Available : false

Family: Red Hat Local Security Checks

Nessus Plugin ID: 89070 ()

Bugtraq ID:

CVE ID: CVE-2015-0293

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