Off-by-one error in monitor.c in Qemu 0.9.1 might make it easier for remote attackers to guess the VNC password, which is limited to seven characters where eight was intended. http://lists.gnu.org/archive/html/qemu-devel/2008-11/msg01224.html http://lists.gnu.org/archive/html/qemu-devel/2008-12/msg00498.html http://svn.savannah.gnu.org/viewvc/?view=rev&root=qemu&revision=5966 http://svn.savannah.gnu.org/viewvc/trunk/monitor.c?root=qemu&r1=5966&r2=5965&pathrev=5966
More information on setting VNC passwords for Qemu/KVM guests can be found here: http://www.linux-kvm.com/content/securing-your-vnc-headless-guest-simple-passwords http://bellard.org/qemu/qemu-doc.html#SEC36 Looking at various version of Qemu, KVM and Xen shipped, following seem to be affected: - Qemu - All versions shipped in stable Fedora versions are currently based on upstream version 0.9.1 that contains this flaw. - KVM - Current versions in stable Fedora versions (65-15.fc9 and 74-10.fc10) contain this problem as well. Issue was fixed in KVM upstream git report via: http://git.kernel.org/?p=virt/kvm/kvm-userspace.git;a=commitdiff;h=003afe2201 and the fix is included in version 82 and later. - Xen - Version of Xen as shipped in Red Hat Enterprise Linux 5 (3.0.3-80.el5) and Fedora 9 (3.2.0-15.fc9) are not affected by this flaw (longer (256) buffer used, full buffer size passed to monitor_readline()). The flaw exists in Fedora 10 and Rawhide Xen versions (3.3.0-1.fc10 and 3.3.1-2.fc11, ioemu-qemu-xen). Is there any way to run Qemu / KVM with monitor enabled when used with libvirt? From the search through the XML format spec, there does not seem to be any option to enable it. Is there a way to enable monitor in qemu-dm used by Xen?
Oh god, will those CVEs on vnc ever stop?