RHSA-2015:1931 - Security Advisory

Topic

Updated qemu-kvm-rhev packages that fix one security issue are now
available for Red Hat Enterprise Virtualization Hypervisor 7.

Red Hat Product Security has rated this update as having Moderate 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.

Description

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

It was found that the QEMU's websocket frame decoder processed incoming
frames without limiting resources used to process the header and the
payload. An attacker able to access a guest's VNC console could use this
flaw to trigger a denial of service on the host by exhausting all available
memory and CPU. (CVE-2015-1779)

This issue was discovered by Daniel P. Berrange of Red Hat.

All qemu-kvm-rhev 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.

Solution

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:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Virtualization 3 for RHEL 7 x86_64

Fixes

• BZ - 1199572 - CVE-2015-1779 qemu: vnc: insufficient resource limiting in VNC websockets decoder

CVEs

• CVE-2015-1779

References

• https://access.redhat.com/security/updates/classification/#moderate