RHEL 6 : qemu-kvm-rhev (RHSA-2012:1233)

high Nessus Plugin ID 78932

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Synopsis

The remote Red Hat host is missing a security update for qemu-kvm-rhev.

Description

The remote Redhat Enterprise Linux 6 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2012:1233 advisory.

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on AMD64 and Intel 64 systems. The qemu-kvm-rhev packages form the user-space component for running virtual machines using KVM.

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)

When using qemu-kvm-rhev on a Red Hat Enterprise Linux 6 host not managed by Red Hat Enterprise Virtualization:

* 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) without the -nodefaults option, and also without specifying a serial or parallel device, or a virtio-console 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 without -nodefaults on Red Hat Enterprise Linux 6.)

- Guests that were managed via libvirt, such as when using Virtual Machine Manager (virt-manager), but that have a serial or parallel device, or a virtio-console 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.

When using qemu-kvm-rhev on a Red Hat Enterprise Virtualization managed Red Hat Enterprise Linux 6 host:

* This flaw did not affect the default use of a Red Hat Enterprise Virtualization host: it is not possible to add a device that uses a virtual console back-end via Red Hat Enterprise Virtualization Manager.

To specify a virtual console back-end for a device and therefore be vulnerable to this issue, the device would have to be created another way, for example, by using a VDSM hook.

Red Hat would like to thank the Xen project for reporting this issue.

This update also fixes the following bugs:

* Previously, the KVM modules were not loaded by the postinstall scriptlet of RPM scripts. This bug caused various issues and required the system to be rebooted to resolve them. With this update, the modules are loaded properly by the scriptlet and no unnecessary reboots are now required.
(BZ#839897)

* Previously, when a guest was started up with two serial devices, qemu-kvm returned an error message and terminated the boot because IRQ 4 for the ISA bus was being used by both devices. This update fixes the qemu-kvm code, which allows IRQ 4 to be used by more than one device on the ISA bus, and the boot now succeeds in the described scenario. (BZ#840054)

All users of qemu-kvm-rhev are advised to upgrade to these updated packages, which fix these issues. 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.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the RHEL qemu-kvm-rhev package based on the guidance in RHSA-2012:1233.

Plugin Details

Severity: High

ID: 78932

File Name: redhat-RHSA-2012-1233.nasl

Version: 1.11

Type: local

Agent: unix

Family: Red Hat Local Security Checks

Published: 11/8/2014

Updated: 4/15/2025

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.5

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2012-3515

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:qemu-img-rhev, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-rhev-tools, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-rhev, cpe:/o:redhat:enterprise_linux:6

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 9/5/2012

Vulnerability Publication Date: 11/23/2012

Reference Information

CVE: CVE-2012-3515

BID: 55413

CWE: 119

RHSA: 2012:1233

Detections

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