====================================================================

                                CERT-Renater

                     Note d'Information No. 2016/VULN422
_____________________________________________________________________

DATE                : 21/12/2016

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running Citrix XenServer versions 7.0,
                                  6.5, 6.2.0, 6.0.2.

=====================================================================
https://support.citrix.com/article/CTX219378
____________________________________________________________________

Citrix XenServer Multiple Security Updates

Security Bulletin | Medium | Created: 21 Dec 2016 | Modified: 21 Dec 2016

Applicable Products

     XenServer 7.0
     XenServer 6.5
     XenServer 6.2.0
     XenServer 6.0.2


Description of Problem

Security vulnerabilities have been identified in Citrix XenServer that
may allow malicious code running within a guest VM to read a small part
of hypervisor memory and allow privileged-mode code running within a
guest VM to hang or crash the host.

These vulnerabilities affect all currently supported versions of Citrix
XenServer up to and including Citrix XenServer 7.0.

The following vulnerabilities have been addressed:

     CVE-2016-9932 (Low): x86 CMPXCHG8B emulation fails to ignore
operand size override
     CVE-2016-10024 (Medium): x86 PV guests may be able to mask
interrupts
     CVE-2016-10025 (Low): missing NULL pointer check in VMFUNC emulation


Mitigating Factors

The ability to read a small amount of hypervisor memory is restricted
to privileged-mode code in all guests except on Citrix XenServer 6.2
SP1 and 6.0.2CC where the attack may also be performed from
non-privileged mode code in HVM guest VMs.

The ability for privileged-mode code in HVM guest VMs to crash the host
is restricted to AMD systems running Citrix XenServer 7.0.


What Customers Should Do

Hotfixes have been released to address these issues. Citrix strongly
recommends that affected customers install these hotfixes, which can be
downloaded from the following locations:

Citrix XenServer 7.0: CTX219498 – 
https://support.citrix.com/article/CTX219498

Citrix XenServer 6.5 SP1: CTX219499 – 
https://support.citrix.com/article/CTX219499

Citrix XenServer 6.2 SP1: CTX219500 – 
https://support.citrix.com/article/CTX219500

Citrix XenServer 6.0.2 Common Criteria: CTX219501 – 
https://support.citrix.com/article/CTX219501


What Citrix Is Doing

Citrix is notifying customers and channel partners about this potential
security issue. This article is also available from the Citrix
Knowledge Center at  http://support.citrix.com/.


Obtaining Support on This Issue

If you require technical assistance with this issue, please contact
Citrix Technical Support. Contact details for Citrix Technical Support
are available at
https://www.citrix.com/support/open-a-support-case.html.


Reporting Security Vulnerabilities

Citrix welcomes input regarding the security of its products and
considers any and all potential vulnerabilities seriously. For guidance
on how to report security-related issues to Citrix, please see the
following document: CTX081743 – Reporting Security Issues to Citrix


Changelog               Date  Change
21st December 2016 	Initial publishing

==========================================================
Serveur de référence du CERT-Renater
https://services.renater.fr/ssi/
==========================================================
+ CERT-RENATER          | tel : 01-53-94-20-44           +
+ 23 - 25 Rue Daviel    | fax : 01-53-94-20-41           +
+ 75013 Paris           | email: cert@support.renater.fr +
==========================================================