(Red Hat Issues Fix) QEMU Floppy Disk Controller Emulation Flaw Lets Local Users Gain Elevated Privileges
SecurityTracker Alert ID: 1032409|
SecurityTracker URL: http://securitytracker.com/id/1032409
(Links to External Site)
Date: May 27 2015
User access via local system|
Fix Available: Yes Vendor Confirmed: Yes |
Version(s): 2.3.0 and prior versions|
A vulnerability was reported in QEMU. A local user on the guest system can obtain elevated privileges on the target host system.|
A local user on the guest system can supply specially crafted commands (e.g., FD_CMD_READ_ID, FD_CMD_DRIVE_SPECIFICATION_COMMAND) to trigger a memory corruption error and execute arbitrary code on the target host system with the privileges of the QEMU process on the host.
VMware, Microsoft Hyper-V, and Bochs hypervisors are not affected.
The original advisory is available at:
Jason Geffner, CrowdStrike Senior Security Researcher, reported this vulnerability.
A local user on the guest system can obtain elevated privileges on the target host system.|
Red Hat has issued a fix.|
The Red Hat advisory is available at:
Vendor URL: wiki.qemu.org/Main_Page (Links to External Site)
Access control error|
|Underlying OS: Linux (Red Hat Enterprise)|
|Underlying OS Comments: 6.5|
This archive entry is a follow-up to the message listed below.|
Source Message Contents
Subject: [RHSA-2015:1031-01] Important: qemu-kvm security update|
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Red Hat Security Advisory
Synopsis: Important: qemu-kvm security update
Advisory ID: RHSA-2015:1031-01
Product: Red Hat Enterprise Linux
Advisory URL: https://rhn.redhat.com/errata/RHSA-2015-1031.html
Issue date: 2015-05-27
CVE Names: CVE-2015-3456
Updated qemu-kvm packages that fix one security issue are now available for
Red Hat Enterprise Linux 6.5 Extended Update Support.
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
2. Relevant releases/architectures:
Red Hat Enterprise Linux HPC Node EUS (v. 6.5) - x86_64
Red Hat Enterprise Linux Server EUS (v. 6.5) - i386, x86_64
KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. The qemu-kvm package provides the
user-space component for running virtual machines using KVM.
An out-of-bounds memory access flaw was found in the way QEMU's virtual
Floppy Disk Controller (FDC) handled FIFO buffer access while processing
certain FDC commands. A privileged guest user could use this flaw to crash
the guest or, potentially, execute arbitrary code on the host with the
privileges of the host's QEMU process corresponding to the guest.
Red Hat would like to thank Jason Geffner of CrowdStrike for reporting
All qemu-kvm users are advised to upgrade to these updated packages, which
contain a backported patch to correct this issue. After installing this
update, shut down all running virtual machines. Once all virtual machines
have shut down, start them again for this update to take effect.
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:
5. Bugs fixed (https://bugzilla.redhat.com/):
1218611 - CVE-2015-3456 qemu: fdc: out-of-bounds fifo buffer memory access
6. Package List:
Red Hat Enterprise Linux HPC Node EUS (v. 6.5):
Red Hat Enterprise Linux Server EUS (v. 6.5):
These packages are GPG signed by Red Hat for security. Our key and
details on how to verify the signature are available from
The Red Hat security contact is <firstname.lastname@example.org>. More contact
details at https://access.redhat.com/security/team/contact/
Copyright 2015 Red Hat, Inc.
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