xend in Xen 3.0.3 does not properly limit the contents of the /local/domain xenstore directory tree, and does not properly restrict a guest VM's write access within this tree, which allows guest OS users to cause a denial of service and possibly have unspecified other impact by writing to (1) console/tty, (2) console/limit, or (3) image/device-model-pid. NOTE: this issue was originally reported as an issue in libvirt 0.3.3 and xenstore, but CVE is considering the core issue to be related to Xen.

The remote OracleVM system is missing necessary patches to address critical security updates :

  - Fix permissions problem with VM.GuestMetrics [bugz 7265]

  - Disable     ovs-disabled-create-netif-if-vif-type-set-ioemu.patch

  - Include proper patch for bugz 7807

  - Implement VM.GuestMetrics to communicate info with guest     OS [bugz 7265]

  - Support long command line [bugz 7264]

  - Fix bug in valid_object function in XendAPI.py [bugz     7363]

  - Update MAC address for HVM guest after live migration     [bugz 7978] [bug 7573550]

  - Fix problem preventing guest from rebooting after     migration [bugz 7807]

  - Fix guest hang when migrating HVM guests in parallel     [bugz #7816] 

  - Disable creating backend network device when vif type     set ioemu [bugz #7592] 

  - pull in cs18449 from xen-3.3-stable 

  - fix invalid reference to XendDomain.VMROOT 

  - Updates from EL5U2 for (CVE-2008-4405, CVE-2008-4993)

  - Fix unsafe use of xenstore data (CVE-2008-4405)

  - Remove qemu-dm.debug wrapper script (CVE-2008-4993)

  - Fix reboots after CVE-2008-4405 changes

  - Fix block-detach regression due to (CVE-2008-4405)

  - make coredump-[destroy|restart] work through traditional     domU config, back ported from xen unstable cs16989

From Red Hat Security Advisory 2009:0003 :

Updated xen packages that resolve several security issues and a bug are now available for Red Hat Enterprise Linux 5.

This update has been rated as having moderate security impact by the Red Hat Security Response Team.

The xen packages contain the Xen tools and management daemons needed to manage virtual machines running on Red Hat Enterprise Linux.

Xen was found to allow unprivileged DomU domains to overwrite xenstore values which should only be changeable by the privileged Dom0 domain.
An attacker controlling a DomU domain could, potentially, use this flaw to kill arbitrary processes in Dom0 or trick a Dom0 user into accessing the text console of a different domain running on the same host. This update makes certain parts of the xenstore tree read-only to the unprivileged DomU domains. (CVE-2008-4405)

It was discovered that the qemu-dm.debug script created a temporary file in /tmp in an insecure way. A local attacker in Dom0 could, potentially, use this flaw to overwrite arbitrary files via a symlink attack. Note: This script is not needed in production deployments and therefore was removed and is not shipped with updated xen packages.
(CVE-2008-4993)

This update also fixes the following bug :

* xen calculates its running time by adding the hypervisor's up-time to the hypervisor's boot-time record. In live migrations of para-virtualized guests, however, the guest would over-write the new hypervisor's boot-time record with the boot-time of the previous hypervisor. This caused time-dependent processes on the guests to fail (for example, crond would fail to start cron jobs). With this update, the new hypervisor's boot-time record is no longer over-written during live migrations.

All xen users are advised to upgrade to these updated packages, which contain backported patches to resolve these issues. The Xen host must be restarted for the update to take effect.

Xen was found to allow unprivileged DomU domains to overwrite xenstore values which should only be changeable by the privileged Dom0 domain.
An attacker controlling a DomU domain could, potentially, use this flaw to kill arbitrary processes in Dom0 or trick a Dom0 user into accessing the text console of a different domain running on the same host. This update makes certain parts of the xenstore tree read-only to the unprivileged DomU domains. (CVE-2008-4405)

It was discovered that the qemu-dm.debug script created a temporary file in /tmp in an insecure way. A local attacker in Dom0 could, potentially, use this flaw to overwrite arbitrary files via a symlink attack. Note: This script is not needed in production deployments and therefore was removed and is not shipped with updated xen packages.
(CVE-2008-4993)

This update also fixes the following bug :

  - xen calculates its running time by adding the     hypervisor's up-time to the hypervisor's boot-time     record. In live migrations of para-virtualized guests,     however, the guest would over-write the new hypervisor's     boot-time record with the boot-time of the previous     hypervisor. This caused time-dependent processes on the     guests to fail (for example, crond would fail to start     cron jobs). With this update, the new hypervisor's     boot-time record is no longer over-written during live     migrations.

The Xen host must be restarted for the update to take effect.

Updated xen packages that resolve several security issues and a bug are now available for Red Hat Enterprise Linux 5.

This update has been rated as having moderate security impact by the Red Hat Security Response Team.

The xen packages contain the Xen tools and management daemons needed to manage virtual machines running on Red Hat Enterprise Linux.

Xen was found to allow unprivileged DomU domains to overwrite xenstore values which should only be changeable by the privileged Dom0 domain.
An attacker controlling a DomU domain could, potentially, use this flaw to kill arbitrary processes in Dom0 or trick a Dom0 user into accessing the text console of a different domain running on the same host. This update makes certain parts of the xenstore tree read-only to the unprivileged DomU domains. (CVE-2008-4405)

It was discovered that the qemu-dm.debug script created a temporary file in /tmp in an insecure way. A local attacker in Dom0 could, potentially, use this flaw to overwrite arbitrary files via a symlink attack. Note: This script is not needed in production deployments and therefore was removed and is not shipped with updated xen packages.
(CVE-2008-4993)

This update also fixes the following bug :

* xen calculates its running time by adding the hypervisor's up-time to the hypervisor's boot-time record. In live migrations of para-virtualized guests, however, the guest would over-write the new hypervisor's boot-time record with the boot-time of the previous hypervisor. This caused time-dependent processes on the guests to fail (for example, crond would fail to start cron jobs). With this update, the new hypervisor's boot-time record is no longer over-written during live migrations.

All xen users are advised to upgrade to these updated packages, which contain backported patches to resolve these issues. The Xen host must be restarted for the update to take effect.

xend did not properly enforce access control of the xenstore directory tree, therefore allowing guest VM's to write there. This could lead to security problems if other applications such as libvirt are not prepared for untrusted data in the xenstore directory (CVE-2008-4405).

The remote Redhat Enterprise Linux 5 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2009:0003 advisory.

    The xen packages contain the Xen tools and management daemons needed to     manage virtual machines running on Red Hat Enterprise Linux.

    Xen was found to allow unprivileged DomU domains to overwrite xenstore     values which should only be changeable by the privileged Dom0 domain. An     attacker controlling a DomU domain could, potentially, use this flaw to     kill arbitrary processes in Dom0 or trick a Dom0 user into accessing the     text console of a different domain running on the same host. This update     makes certain parts of the xenstore tree read-only to the unprivileged DomU     domains. (CVE-2008-4405)

    It was discovered that the qemu-dm.debug script created a temporary file in     /tmp in an insecure way. A local attacker in Dom0 could, potentially, use     this flaw to overwrite arbitrary files via a symlink attack. Note: This     script is not needed in production deployments and therefore was removed     and is not shipped with updated xen packages. (CVE-2008-4993)

    This update also fixes the following bug:

    * xen calculates its running time by adding the hypervisor's up-time to the     hypervisor's boot-time record. In live migrations of para-virtualized     guests, however, the guest would over-write the new hypervisor's boot-time     record with the boot-time of the previous hypervisor. This caused     time-dependent processes on the guests to fail (for example, crond would     fail to start cron jobs). With this update, the new hypervisor's boot-time     record is no longer over-written during live migrations.

    All xen users are advised to upgrade to these updated packages, which     contain backported patches to resolve these issues. The Xen host must be     restarted for the update to take effect.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
79451	OracleVM 2.1 : xen (OVMSA-2009-0001)	Nessus	OracleVM Local Security Checks	high
67782	Oracle Linux 5 : xen (ELSA-2009-0003)	Nessus	Oracle Linux Local Security Checks	high
60515	Scientific Linux Security Update : xen on SL5.x i386/x86_64	Nessus	Scientific Linux Local Security Checks	high
43723	CentOS 5 : xen (CESA-2009:0003)	Nessus	CentOS Local Security Checks	high
40844	openSUSE Security Update : xen (xen-1239)	Nessus	SuSE Local Security Checks	high
35300	RHEL 5 : xen (RHSA-2009:0003)	Nessus	Red Hat Local Security Checks	medium

Detections

Analytics

CVE-2008-4405

critical

Tenable Plugins

high

high

high

high

high

medium