USN-1063-1: QEMU vulnerability

14 February 2011

qemu-kvm vulnerability

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

  • Ubuntu 10.10
  • Ubuntu 10.04 LTS
  • Ubuntu 9.10


Blank passwords allowed unrestricted QEMU VNC session access.

Software Description

  • qemu-kvm - Full virtualization on i386 and amd64 hardware


Neil Wilson discovered that if VNC passwords were blank in QEMU configurations, access to VNC sessions was allowed without a password instead of being disabled. A remote attacker could connect to running VNC sessions of QEMU and directly control the system. By default, QEMU does not start VNC sessions.

Update instructions

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

Ubuntu 10.10
kvm - 0.12.5+noroms-0ubuntu7.2
qemu - 0.12.5+noroms-0ubuntu7.2
qemu-arm-static - 0.12.5+noroms-0ubuntu7.2
qemu-kvm - 0.12.5+noroms-0ubuntu7.2
qemu-kvm-extras - 0.12.5+noroms-0ubuntu7.2
qemu-kvm-extras-static - 0.12.5+noroms-0ubuntu7.2
Ubuntu 10.04 LTS
kvm - 0.12.3+noroms-0ubuntu9.4
qemu - 0.12.3+noroms-0ubuntu9.4
qemu-arm-static - 0.12.3+noroms-0ubuntu9.4
qemu-common - 0.12.3+noroms-0ubuntu9.4
qemu-kvm - 0.12.3+noroms-0ubuntu9.4
qemu-kvm-extras - 0.12.3+noroms-0ubuntu9.4
qemu-kvm-extras-static - 0.12.3+noroms-0ubuntu9.4
Ubuntu 9.10
kvm - 0.11.0-0ubuntu6.4
qemu - 0.11.0-0ubuntu6.4
qemu-arm-static - 0.11.0-0ubuntu6.4
qemu-kvm - 0.11.0-0ubuntu6.4
qemu-kvm-extras - 0.11.0-0ubuntu6.4

To update your system, please follow these instructions:

After a standard system update you need to restart any running QEMU sessions to make all the necessary changes.