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Liebe Kolleginnen und Kollegen,
soeben erreichte uns nachfolgendes RedHat Security Advisory. Wir geben
diese Informationen unveraendert an Sie weiter.
CVE-2008-4405 – Schwachstelle in Xen
Das Virtualisierungssystem Xen enthaelt eine Schwachstelle bei der
Zugriffsverwaltung auf Kontrollstrukturen im lokalen Dateisystem.
Dabei werden die Schreibrechte eines Benutzers des Gastsystems
fehlerhaft geprueft, was dazu fuehrt, dass ein lokaler Angreifer
Kontrolldaten ueberschreiben kann. Die Schwachstelle kann fuer Denial
of Service Angriffe, potentiell aber auch andere Arten von Angriffen
ausgenutzt werden.
CVE-2008-4993 – Symlink Schwachstelle in Xen/Qemu
Qemu legt temporaere Verzeichnisse auf eine unsichere Weise an. Dabei
wird nicht ueberprueft, ob beim Erstellen des Verzeichnisses eine
bereits bestehende Datei ueberschrieben wird. Ein lokaler Angreifer
kann diese Schwachstelle ausnutzen, um mit Hilfe praeparierter
Symlinks beliebige Dateien auf der Festplatte zu ueberschreiben.
Betroffen sind die folgenden Software Pakete und Plattformen:
Paket xen
Red Hat Enterprise Linux Desktop (v. 5 client) – i386, x86_64
RHEL Desktop Multi OS (v. 5 client) – i386, x86_64
Red Hat Enterprise Linux (v. 5 server) – i386, ia64, x86_64
RHEL Virtualization (v. 5 server) – i386, ia64, x86_64
Vom Hersteller werden ueberarbeitete Pakete zur Verfuegung gestellt.
Hersteller Advisory:
https://rhn.redhat.com/errata/RHSA-2009-0003.html
(c) der deutschen Zusammenfassung bei DFN-CERT Services GmbH; die
Verbreitung, auch auszugsweise, ist nur unter Hinweis auf den Urheber,
DFN-CERT Services GmbH, und nur zu nicht kommerziellen Zwecken
gestattet.
Mit freundlichen Gruessen,
Michael Groening, DFN-CERT
– —
Michael Groening (Incident Response Team), +49 40 808077-555
DFN-CERT Services GmbH, https://www.dfn-cert.de, Phone +49 40 808077-555
Sitz / Register: Hamburg, AG Hamburg, HRB 88805, Ust-IdNr.: DE 232129737
Sachsenstrasse 5, 20097 Hamburg/Germany, CEO: Dr. Klaus-Peter Kossakowski
Automatische Warnmeldungen https://www.cert.dfn.de/autowarn
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=====================================================================
Red Hat Security Advisory
Synopsis: Moderate: xen security and bug fix update
Advisory ID: RHSA-2009:0003-01
Product: Red Hat Enterprise Linux
Advisory URL: https://rhn.redhat.com/errata/RHSA-2009-0003.html
Issue date: 2009-01-07
CVE Names: CVE-2008-4405 CVE-2008-4993
=====================================================================
1. Summary:
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.
2. Relevant releases/architectures:
Red Hat Enterprise Linux Desktop (v. 5 client) – i386, x86_64
RHEL Desktop Multi OS (v. 5 client) – i386, x86_64
Red Hat Enterprise Linux (v. 5 server) – i386, ia64, x86_64
RHEL Virtualization (v. 5 server) – i386, ia64, x86_64
3. Description:
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.
4. Solution:
Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.
This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259
5. Bugs fixed (http://bugzilla.redhat.com/):
464455 – timer stops running after live migrate or dom0 reboot & save/restore of a Xen guest
464817 – CVE-2008-4405 xen: Multiple unsafe uses of guest-writable data from xenstore
470795 – CVE-2008-4993 xen: insecure temporary file use in qemu-dm.debug
6. Package List:
Red Hat Enterprise Linux Desktop (v. 5 client):
Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Client/en/os/SRPMS/xen-3.0.3-64.el5_2.9.src.rpm
i386:
xen-debuginfo-3.0.3-64.el5_2.9.i386.rpm
xen-libs-3.0.3-64.el5_2.9.i386.rpm
x86_64:
xen-debuginfo-3.0.3-64.el5_2.9.i386.rpm
xen-debuginfo-3.0.3-64.el5_2.9.x86_64.rpm
xen-libs-3.0.3-64.el5_2.9.i386.rpm
xen-libs-3.0.3-64.el5_2.9.x86_64.rpm
RHEL Desktop Multi OS (v. 5 client):
Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Client/en/os/SRPMS/xen-3.0.3-64.el5_2.9.src.rpm
i386:
xen-3.0.3-64.el5_2.9.i386.rpm
xen-debuginfo-3.0.3-64.el5_2.9.i386.rpm
xen-devel-3.0.3-64.el5_2.9.i386.rpm
x86_64:
xen-3.0.3-64.el5_2.9.x86_64.rpm
xen-debuginfo-3.0.3-64.el5_2.9.i386.rpm
xen-debuginfo-3.0.3-64.el5_2.9.x86_64.rpm
xen-devel-3.0.3-64.el5_2.9.i386.rpm
xen-devel-3.0.3-64.el5_2.9.x86_64.rpm
Red Hat Enterprise Linux (v. 5 server):
Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Server/en/os/SRPMS/xen-3.0.3-64.el5_2.9.src.rpm
i386:
xen-debuginfo-3.0.3-64.el5_2.9.i386.rpm
xen-libs-3.0.3-64.el5_2.9.i386.rpm
ia64:
xen-debuginfo-3.0.3-64.el5_2.9.ia64.rpm
xen-libs-3.0.3-64.el5_2.9.ia64.rpm
x86_64:
xen-debuginfo-3.0.3-64.el5_2.9.i386.rpm
xen-debuginfo-3.0.3-64.el5_2.9.x86_64.rpm
xen-libs-3.0.3-64.el5_2.9.i386.rpm
xen-libs-3.0.3-64.el5_2.9.x86_64.rpm
RHEL Virtualization (v. 5 server):
Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Server/en/os/SRPMS/xen-3.0.3-64.el5_2.9.src.rpm
i386:
xen-3.0.3-64.el5_2.9.i386.rpm
xen-debuginfo-3.0.3-64.el5_2.9.i386.rpm
xen-devel-3.0.3-64.el5_2.9.i386.rpm
ia64:
xen-3.0.3-64.el5_2.9.ia64.rpm
xen-debuginfo-3.0.3-64.el5_2.9.ia64.rpm
xen-devel-3.0.3-64.el5_2.9.ia64.rpm
x86_64:
xen-3.0.3-64.el5_2.9.x86_64.rpm
xen-debuginfo-3.0.3-64.el5_2.9.i386.rpm
xen-debuginfo-3.0.3-64.el5_2.9.x86_64.rpm
xen-devel-3.0.3-64.el5_2.9.i386.rpm
xen-devel-3.0.3-64.el5_2.9.x86_64.rpm
These packages are GPG signed by Red Hat for security. Our key and
details on how to verify the signature are available from
https://www.redhat.com/security/team/key/#package
7. References:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-4405
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-4993
http://www.redhat.com/security/updates/classification/#moderate
8. Contact:
The Red Hat security contact is
details at https://www.redhat.com/security/team/contact/
Copyright 2009 Red Hat, Inc.
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