ESB-2017.2585 - [Win][Appliance] XenServer: Root compromise - Existing account 2017-10-13

Printable version
PGP/GPG verifiable version

Hash: SHA256

             AUSCERT External Security Bulletin Redistribution

                Citrix XenServer Multiple Security Updates
                              13 October 2017


        AusCERT Security Bulletin Summary

Product:           XenServer
Publisher:         Citrix
Operating System:  Windows
                   Network Appliance
Impact/Access:     Root Compromise -- Existing Account
Resolution:        Patch/Upgrade

Original Bulletin:

- --------------------------BEGIN INCLUDED TEXT--------------------


Citrix XenServer Multiple Security Updates

Security Bulletin | High | Created: 12 Oct 2017 | Modified: 12 Oct 2017

Applicable Products

XenServer 7.2XenServer 7.1 LTSR Cumulative Update 1XenServer 7.1XenServer 
7.0XenServer 6.5XenServer 6.2.0XenServer 6.0.2

Description of Problem

A number of security vulnerabilities have been identified in Citrix
XenServer that may allow a malicious administrator of a guest VM to
compromise the host.

These vulnerabilities affect all currently supported versions of
Citrix XenServer up to and including Citrix XenServer 7.2.

The following vulnerabilities have been addressed:
CVE-2017-TBA0: Unlimited recursion in linear pagetable
CVE-2017-TBA1: Stale TLB entry due to page type
release race 
CVE-2017-TBA2: page type reference leak on x86 
CVE-2017-TBA3: x86: Incorrect handling of self-linear shadow mappings with 
translated guests 
CVE-2017-TBA4: x86: Incorrect handling of IST settings during CPU hotplug
CVE-2017-TBA7: multiple MSI mapping issues on x86
CVE-2017-TBA9: hypervisor stack leak in x86 I/O intercept code 

For customers that do not have PV-based guests, are not using PCI
passthrough and are using hardware with HAP support, the risk is
reduced to a disclosure of a small part of the hypervisor stack.

What Customers Should Do

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

Citrix XenServer 7.2: CTX228722 
Citrix XenServer 7.1 LTSR CU1: CTX228721 
Citrix XenServer 7.1 LTSR: CTX228720 
Citrix XenServer 7.0: CTX228719 
Citrix XenServer 6.5 SP1: CTX228718 
Citrix XenServer 6.2 SP1: CTX228717 
Citrix XenServer 6.0.2 Common Criteria: CTX228716

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

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 

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


12th October 2017
Initial publishing

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

Australian Computer Emergency Response Team
The University of Queensland
Qld 4072

Internet Email:
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.


« Back to bulletins