Red Hat Security Advisory: kvm security update Security Advisory secalert@redhat.com Red Hat Security Response Team RHSA-2012:1235 Final 1 1 2012-09-05T16:40:00Z Current version 2012-09-05T16:40:00Z 2012-09-05T16:40:00Z Red Hat rhsa-to-cvrf 1.0.1484 2012-09-05T16:50:07Z Updated kvm packages that fix one security issue are now available for Red Hat Enterprise Linux 5. The Red Hat Security Response Team 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. 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 QEMU handled VT100 terminal escape sequences when emulating certain character devices. A guest user with privileges to write to a character device that is emulated on the host using a virtual console back-end could use this flaw to crash the qemu-kvm process on the host or, possibly, escalate their privileges on the host. (CVE-2012-3515) This flaw did not affect the default use of KVM. Affected configurations were: * When guests were started from the command line ("/usr/libexec/qemu-kvm"), and without specifying a serial or parallel device that specifically does not use a virtual console (vc) back-end. (Note that Red Hat does not support invoking "qemu-kvm" from the command line on Red Hat Enterprise Linux 5.) * Guests that were managed via libvirt, such as when using Virtual Machine Manager (virt-manager), but that have a serial or parallel device that uses a virtual console back-end. By default, guests managed via libvirt will not use a virtual console back-end for such devices. Red Hat would like to thank the Xen project for reporting this issue. All KVM users should upgrade to these updated packages, which correct this issue. Note: The procedure in the Solution section must be performed before this update will take effect. Please see https://www.redhat.com/footer/terms-of-use.html Copyright © 2012 Red Hat, Inc. All rights reserved. Important https://rhn.redhat.com/errata/RHSA-2012-1235.html https://rhn.redhat.com/errata/RHSA-2012-1235.html https://access.redhat.com/security/updates/classification/#important https://access.redhat.com/security/updates/classification/#important RHEL Virtualization (v. 5 server) RHEL Desktop Multi OS (v. 5 client) kvm-83-249.el5_8.5.src.rpm kvm-83-249.el5_8.5 as a component of RHEL Virtualization (v. 5 server) kvm-83-249.el5_8.5 as a component of RHEL Desktop Multi OS (v. 5 client) A flaw was found in the way QEMU handled VT100 terminal escape sequences when emulating certain character devices. A guest user with privileges to write to a character device that is emulated on the host using a virtual console back-end could use this flaw to crash the qemu-kvm process on the host or, possibly, escalate their privileges on the host. 2012-08-23T00:00:00Z 2012-09-05T00:00:00Z CVE-2012-3515 5Client-VT-5.8.Z:kvm-83-249.el5_8.5 5Server-VT-5.8.Z:kvm-83-249.el5_8.5 Important 7.4 AV:A/AC:M/Au:S/C:C/I:C/A:C 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/knowledge/articles/11258 The following procedure must be performed before this update will take effect: 1) Stop all KVM guest virtual machines. 2) Either reboot the hypervisor machine or, as the root user, remove (using "modprobe -r [module]") and reload (using "modprobe [module]") all of the following modules which are currently running (determined using "lsmod"): kvm, ksm, kvm-intel or kvm-amd. 3) Restart the KVM guest virtual machines. https://rhn.redhat.com/errata/RHSA-2012-1235.html https://www.redhat.com/security/data/cve/CVE-2012-3515.html CVE-2012-3515 https://bugzilla.redhat.com/show_bug.cgi?id=851252 bz#851252: CVE-2012-3515 qemu: VT100 emulation vulnerability Red Hat would like to thank the Xen project for reporting this issue.