Vigil@nce - Xen: privilege escalation via VGA Backend
March 2015 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
A local attacker can use the VGA Backend of Xen, in order to
access to a guest system.
Impacted products: Fedora, SUSE Linux Enterprise Desktop, SLES,
Unix (platform)
Severity: 2/4
Creation date: 12/03/2015
DESCRIPTION OF THE VULNERABILITY
When an HVM x86 qemu guest instantiate an emulated VGA device, a
backend is started for SDL or VNC.
However, this backend is started even when the configuration does
not indicate "sdl=1" nor "vnc=1". The impact then depends on the
qemu-xen compilation method:
– if qemu-xen is compiled with SDL: a SDL window is opened with
$DISPLAY
– else: a VNC server listens on localhost
A local attacker can therefore use the VGA Backend of Xen, in
order to access to a guest system.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Xen-privilege-escalation-via-VGA-Backend-16384