RHSA-2016:0379 - Security Advisory

Topic

An updated rhev-hypervisor package that fixes several security issues,
bugs, and enhancements is now available.

Red Hat Product Security has rated this update as having Important
security impact. A Common Vulnerability Scoring System (CVSS) base
score, which gives a detailed severity rating, is available from the
CVE link in the References section.

Description

The rhev-hypervisor package provides a Red Hat Enterprise
Virtualization Hypervisor ISO disk image. The Red Hat Enterprise
Virtualization Hypervisor is a dedicated Kernel-based Virtual Machine
(KVM) hypervisor. It includes everything necessary to run and manage
virtual machines: a subset of the Red Hat Enterprise Linux operating
environment and the Red Hat Enterprise Virtualization Agent.

Note: Red Hat Enterprise Virtualization Hypervisor is only available
for the Intel 64 and AMD64 architectures with virtualization
extensions.

A padding oracle flaw was found in the Secure Sockets Layer version
2.0 (SSLv2) protocol. An attacker could 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. For more information, refer to
the knowledge base article linked in the References section.

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)

A side-channel attack was found that makes use of cache-bank
conflicts on the Intel Sandy-Bridge microarchitecture. An attacker
who has the ability to control code in a thread running on the same
hyper-threaded core as the victim's thread that is performing
decryption, could use this flaw to recover RSA private keys.
(CVE-2016-0702)

A double-free flaw was found in the way OpenSSL parsed certain
malformed DSA (Digital Signature Algorithm) private keys. An
attacker could create specially crafted DSA private keys that, when
processed by an application compiled against OpenSSL, could cause
the application to crash. (CVE-2016-0705)

An integer overflow flaw, leading to a NULL pointer dereference or a
heap-based memory corruption, was found in the way some BIGNUM
functions of OpenSSL were implemented. Applications that use these
functions with large untrusted input could crash or, potentially,
execute arbitrary code. (CVE-2016-0797)

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; Yuval
Yarom (University of Adelaide and NICTA), Daniel Genkin (Technion
and Tel Aviv University), Nadia Heninger (University of Pennsylvania)
as the original reporters of CVE-2016-0702; Adam Langley (Google/
BoringSSL) as the original reporter of CVE-2016-0705; and Guido
Vranken as the original reporter of CVE-2016-0797.

All openssl users are advised to upgrade to this updated package,
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.

Changes to the rhev-hypervisor component:

• Previously, a race between services during boot prevented network

configuration from upgrading correctly. The risk for the race has
now been reduced significantly to allow the upgrade of the network
configuration to complete correctly. (BZ#1194068)

• Previously, using the text user interface (TUI) to log in to the

administrator account of Red Hat Enterprise Virtualization
Hypervisor failed with a Python backtrace. This update makes the
"six" module correctly importable under all circumstances, which
ensures that logging in to Red Hat Enterprise Virtualization
Hypervisor using TUI proceeds as expected. (BZ#1246836)

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

Affected Products

• Red Hat Virtualization 7 x86_64
• Red Hat Virtualization 6 x86_64

Fixes

• BZ - 1194068 - vdsm-3.5 network conf upgrade fails, due to `service network restart` by node
• BZ - 1236508 - [Tracker] Build RHEV-H for RHEV 3.6.0
• BZ - 1283498 - messages log flooded with 'Failed to reset devices.list on /machine.slice: Invalid argument'
• BZ - 1301846 - CVE-2015-3197 OpenSSL: SSLv2 doesn't block disabled ciphers
• BZ - 1302248 - RHEV-H 7.2 RC1: Remove "Beta" keyword from plymouth
• BZ - 1310593 - CVE-2016-0800 SSL/TLS: Cross-protocol attack on TLS using SSLv2 (DROWN)
• BZ - 1310596 - CVE-2016-0705 OpenSSL: Double-free in DSA code
• BZ - 1310599 - CVE-2016-0702 OpenSSL: Side channel attack on modular exponentiation
• BZ - 1311880 - CVE-2016-0797 OpenSSL: BN_hex2bn/BN_dec2bn NULL pointer deref/heap corruption

CVEs

• CVE-2016-0797
• CVE-2016-0702
• CVE-2016-0705
• CVE-2016-0800
• CVE-2015-3197

References

• https://access.redhat.com/security/updates/classification/#important