==========================================================================
Ubuntu Security Notice USN-3575-2
March 05, 2018

qemu regression
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

USN-3575-1 introduced a regression in QEMU.

Software Description:
- qemu: Machine emulator and virtualizer

Details:

USN-3575-1 fixed vulnerabilities in QEMU. The fix for CVE-2017-11334 caused
a regression in Xen environments. This update removes the problematic fix
pending further investigation.

We apologize for the inconvenience.

Original advisory details:

 It was discovered that QEMU incorrectly handled guest ram. A privileged
 attacker inside the guest could use this issue to cause QEMU to crash,
 resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS
 and Ubuntu 16.04 LTS. (CVE-2017-11334)
  David Buchanan discovered that QEMU incorrectly handled the VGA device. A
 privileged attacker inside the guest could use this issue to cause QEMU to
 crash, resulting in a denial of service. This issue was only addressed in
 Ubuntu 17.10. (CVE-2017-13672)
  Thomas Garnier discovered that QEMU incorrectly handled multiboot. An
 attacker could use this issue to cause QEMU to crash, resulting in a denial
 of service, or possibly execute arbitrary code on the host. In the default
 installation, when QEMU is used with libvirt, attackers would be isolated
 by the libvirt AppArmor profile. This issue only affected Ubuntu 14.04 LTS
 and Ubuntu 16.04 LTS. (CVE-2017-14167)
  Tuomas Tynkkynen discovered that QEMU incorrectly handled VirtFS directory
 sharing. An attacker could use this issue to obtain sensitive information
 from host memory. (CVE-2017-15038)
  Eric Blake discovered that QEMU incorrectly handled memory in the
 NBD server. An attacker could use this issue to cause the NBD server to
 crash, resulting in a denial of service. This issue only affected Ubuntu
 17.10. (CVE-2017-15118)
  Eric Blake discovered that QEMU incorrectly handled certain options to the
 NBD server. An attacker could use this issue to cause the NBD server to
 crash, resulting in a denial of service. This issue only affected Ubuntu
 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2017-15119)
  Daniel Berrange discovered that QEMU incorrectly handled the VNC server. A
 remote attacker could possibly use this issue to consume memory, resulting
 in a denial of service. This issue was only addressed in Ubuntu 17.10.
 (CVE-2017-15124)
  Carl Brassey discovered that QEMU incorrectly handled certain websockets. A
 remote attacker could possibly use this issue to consume memory, resulting
 in a denial of service. This issue only affected Ubuntu 17.10.
 (CVE-2017-15268)
  Guoxiang Niu discovered that QEMU incorrectly handled the Cirrus VGA
 device. A privileged attacker inside the guest could use this issue to
 cause QEMU to crash, resulting in a denial of service. (CVE-2017-15289)
  Cyrille Chatras discovered that QEMU incorrectly handled certain PS2 values
 during migration. An attacker could possibly use this issue to cause QEMU
 to crash, resulting in a denial of service, or possibly execute arbitrary
 code. This issue only affected Ubuntu 16.04 LTS and Ubuntu 17.10.
 (CVE-2017-16845)
  It was discovered that QEMU incorrectly handled the Virtio Vring
 implementation. An attacker could possibly use this issue to cause QEMU to
 crash, resulting in a denial of service. This issue only affected Ubuntu
 16.04 LTS and Ubuntu 17.10. (CVE-2017-17381)
  Eric Blake discovered that QEMU incorrectly handled certain rounding
 operations. An attacker could possibly use this issue to cause QEMU to
 crash, resulting in a denial of service. This issue only affected Ubuntu
 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2017-18043)
  Jiang Xin and Lin ZheCheng discovered that QEMU incorrectly handled the
 VGA device. A privileged attacker inside the guest could use this issue to
 cause QEMU to crash, resulting in a denial of service. (CVE-2018-5683)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.04 LTS:
  qemu                            1:2.5+dfsg-5ubuntu10.24

Ubuntu 14.04 LTS:
  qemu                            2.0.0+dfsg-2ubuntu1.40

After a standard system update you need to restart all QEMU virtual
machines to make all the necessary changes.

References:
  https://usn.ubuntu.com/usn/usn-3575-2
  https://usn.ubuntu.com/usn/usn-3575-1
  https://launchpad.net/bugs/1752761

Package Information:
  https://launchpad.net/ubuntu/+source/qemu/1:2.5+dfsg-5ubuntu10.24
  https://launchpad.net/ubuntu/+source/qemu/2.0.0+dfsg-2ubuntu1.40