RHSA-2011:1408 - Security Advisory

Topic

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

The Red Hat Security Response Team has rated this update as having moderate
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-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.

The RHBA-2011:1254 update introduced a regression in the Linux kernel's
Ethernet bridge implementation. If a system had an interface in a bridge,
and an attacker on the local network could send packets to that interface,
they could cause a denial of service on that system. (CVE-2011-2942)

A flaw in the Linux kernel could lead to GRO (Generic Receive Offload)
fields being left in an inconsistent state. An attacker on the local
network could use this flaw to trigger a denial of service. GRO is enabled
by default in all network drivers that support it. (CVE-2011-2723)

The way IPv4 and IPv6 protocol sequence numbers and fragment IDs were
generated could allow a man-in-the-middle attacker to inject packets and
possibly hijack connections. Protocol sequence numbers and fragment IDs are
now more random. (CVE-2011-3188)

Non-member VLAN (virtual LAN) packet handling for interfaces in promiscuous
mode and also using the be2net driver could allow an attacker on the local
network to cause a denial of service. (CVE-2011-3347)

Red Hat would like to thank Brent Meshier for reporting CVE-2011-2723; Dan
Kaminsky for reporting CVE-2011-3188; and Somnath Kotur for reporting
CVE-2011-3347.

This updated package provides updated components that include fixes for
numerous security issues. These issues have no security impact on Red Hat
Enterprise Virtualization Hypervisor itself, however.

The security fixes included in this update address the following CVE
numbers:

CVE-2011-2695, CVE-2011-2699, CVE-2011-3191, CVE-2011-1833, CVE-2011-2496,
CVE-2011-3209, CVE-2011-2484, CVE-2011-3131, CVE-2009-4067, CVE-2011-1160,
and CVE-2011-1585 (kernel issues)

CVE-2011-3378 (rpm issues)

Users of Red Hat Enterprise Virtualization Hypervisor should upgrade to
this updated package, which resolves these issues.

Solution

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

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/kb/docs/DOC-11259

Affected Products

• Red Hat Virtualization 5 x86_64

Fixes

• BZ - 726552 - CVE-2011-2723 kernel: gro: only reset frag0 when skb can be pulled
• BZ - 730917 - CVE-2011-2942 kernel: bridge: null pointer dereference in __br_deliver
• BZ - 732658 - CVE-2011-3188 kernel: net: improve sequence number generation
• BZ - 736425 - CVE-2011-3347 kernel: be2net: promiscuous mode and non-member VLAN packets DoS

CVEs

• CVE-2011-3347
• CVE-2011-2942
• CVE-2011-3188
• CVE-2011-2723

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://rhn.redhat.com/errata/RHBA-2011-1254.html