RHEL 5 : kvm (RHSA-2013:0727)

This script is Copyright (C) 2013-2014 Tenable Network Security, Inc.


Synopsis :

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

Description :

Updated kvm packages that fix three security issues are now available
for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team 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.

KVM (Kernel-based Virtual Machine) is a full virtualization solution
for Linux on AMD64 and Intel 64 systems. KVM is a Linux kernel module
built for the standard Red Hat Enterprise Linux kernel.

A flaw was found in the way KVM handled guest time updates when the
buffer the guest registered by writing to the MSR_KVM_SYSTEM_TIME
machine state register (MSR) crossed a page boundary. A privileged
guest user could use this flaw to crash the host or, potentially,
escalate their privileges, allowing them to execute arbitrary code at
the host kernel level. (CVE-2013-1796)

A potential use-after-free flaw was found in the way KVM handled guest
time updates when the GPA (guest physical address) the guest
registered by writing to the MSR_KVM_SYSTEM_TIME machine state
register (MSR) fell into a movable or removable memory region of the
hosting user-space process (by default, QEMU-KVM) on the host. If that
memory region is deregistered from KVM using
KVM_SET_USER_MEMORY_REGION and the allocated virtual memory reused, a
privileged guest user could potentially use this flaw to escalate
their privileges on the host. (CVE-2013-1797)

A flaw was found in the way KVM emulated IOAPIC (I/O Advanced
Programmable Interrupt Controller). A missing validation check in the
ioapic_read_indirect() function could allow a privileged guest user to
crash the host, or read a substantial portion of host kernel memory.
(CVE-2013-1798)

Red Hat would like to thank Andrew Honig of Google for reporting all
of these issues.

All users of kvm are advised to upgrade to these updated packages,
which contain backported patches to correct these issues. Note that
the procedure in the Solution section must be performed before this
update will take effect.

See also :

https://www.redhat.com/security/data/cve/CVE-2013-1796.html
https://www.redhat.com/security/data/cve/CVE-2013-1797.html
https://www.redhat.com/security/data/cve/CVE-2013-1798.html
http://rhn.redhat.com/errata/RHSA-2013-0727.html

Solution :

Update the affected packages.

Risk factor :

Medium / CVSS Base Score : 6.8
(CVSS2#AV:A/AC:H/Au:N/C:C/I:C/A:C)
CVSS Temporal Score : 5.9
(CVSS2#E:ND/RL:OF/RC:C)
Public Exploit Available : false

Family: Red Hat Local Security Checks

Nessus Plugin ID: 65905 ()

Bugtraq ID: 58604
58605
58607

CVE ID: CVE-2013-1796
CVE-2013-1797
CVE-2013-1798