RHSA-2014:1354 - Security Advisory

Topic

An updated rhev-hypervisor6 package that fixes several security issues is
now available.

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

Description

The rhev-hypervisor6 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 flaw was found in the way Bash evaluated certain specially crafted
environment variables. An attacker could use this flaw to override or
bypass environment restrictions to execute shell commands. Certain services
and applications allow remote unauthenticated attackers to provide
environment variables, allowing them to exploit this issue. (CVE-2014-6271)

It was found that the fix for CVE-2014-6271 was incomplete, and Bash still
allowed certain characters to be injected into other environments via
specially crafted environment variables. An attacker could potentially use
this flaw to override or bypass environment restrictions to execute shell
commands. Certain services and applications allow remote unauthenticated
attackers to provide environment variables, allowing them to exploit this
issue. (CVE-2014-7169)

A flaw was found in the way NSS parsed ASN.1 (Abstract Syntax Notation One)
input from certain RSA signatures. A remote attacker could use this flaw to
forge RSA certificates by providing a specially crafted signature to an
application using NSS. (CVE-2014-1568)

It was discovered that the fixed-sized redir_stack could be forced to
overflow in the Bash parser, resulting in memory corruption, and possibly
leading to arbitrary code execution when evaluating untrusted input that
would not otherwise be run as code. (CVE-2014-7186)

An off-by-one error was discovered in the way Bash was handling deeply
nested flow control constructs. Depending on the layout of the .bss
segment, this could allow arbitrary execution of code that would not
otherwise be executed by Bash. (CVE-2014-7187)

Red Hat would like to thank Stephane Chazelas for reporting CVE-2014-6271,
and the Mozilla project for reporting CVE-2014-1568. Upstream acknowledges
Antoine Delignat-Lavaud and Intel Product Security Incident Response Team
as the original reporters of CVE-2014-1568. The CVE-2014-7186 and
CVE-2014-7187 issues were discovered by Florian Weimer of Red Hat Product
Security.

Users of the Red Hat Enterprise Virtualization Hypervisor are advised to
upgrade to this updated package.

Solution

This update is available via the Red Hat Network. Details on how to use the
Red Hat Network to apply this update are available at
https://access.redhat.com/articles/11258

To upgrade Hypervisors in Red Hat Enterprise Virtualization environments
using the disk image provided by this package, refer to:

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Hypervisor_Deployment_Guide/chap-Deployment_Guide-Upgrading_Red_Hat_Enterprise_Virtualization_Hypervisors.html

Affected Products

• Red Hat Virtualization 3.4 x86_64

Fixes

• BZ - 1141597 - CVE-2014-6271 bash: specially-crafted environment variables can be used to inject shell commands
• BZ - 1145429 - CVE-2014-1568 nss: RSA PKCS#1 signature verification forgery flaw (MFSA 2014-73)
• BZ - 1146319 - CVE-2014-7169 bash: code execution via specially-crafted environment (Incomplete fix for CVE-2014-6271)
• BZ - 1146791 - CVE-2014-7186 bash: parser can allow out-of-bounds memory access while handling redir_stack
• BZ - 1146804 - CVE-2014-7187 bash: off-by-one error in deeply nested flow control constructs

CVEs

• CVE-2014-1568
• CVE-2014-6271
• CVE-2014-7169
• CVE-2014-7186
• CVE-2014-7187

References

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