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                             CERT-Renater

                 Note d'Information No. 2018/VULN394
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DATE                : 22/11/2018

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running Citrix XenServer versions 7.6, 7.5,
                                          7.1, 7.0.

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https://support.citrix.com/article/CTX239432
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Citrix XenServer Security Update

Security Bulletin
Created: 20 Nov 2018 | Modified: 20 Nov 2018

Applicable Products

  o XenServer 7.6
  o XenServer 7.5
  o XenServer 7.1 LTSR Cumulative Update 1
  o XenServer 7.0


Description of Problem

A number of security vulnerabilities have been identified in Citrix
XenServer that have deployment-dependent impacts.

These issues affect the following supported versions of Citrix
XenServer:

  o Citrix XenServer 7.6
  o Citrix XenServer 7.5
  o Citrix XenServer 7.1 LTSR CU1
  o Citrix XenServer 7.0

The following issues have been addressed:

  o CVE-2018-TBA1: insufficient TLB flushing/improper large page
mappings with AMD IOMMUs

This issue may allow code in an HVM guest VM to compromise the host.

This issue is limited to guests that are using the PCI passthrough
feature in conjunction with AMD CPUs.

  o CVE-2018-TBA2: x86: DoS from attempting to use INVPCID with a
non-canonical address

This issue may allow privileged code in a PV guest VM to crash the host.

This issue is limited to hosts with Intel CPUs that support the INVPCID
instruction.

This issue only occurs in Citrix XenServer 7.6.

  o Intel Erratum: "Processor May Hang When Executing Code In an HLE
    Transaction".

This issue may allow code running in a guest VM to cause the host to
become unresponsive and/or crash.

This issue is limited to hosts with Intel CPUs that are affected by the
corresponding Intel erratum.



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What Customers Should Do

Hotfixes have been released to address these issues. Citrix recommends
that affected customers install these hotfixes as their patching
schedule permits.
The hotfixes can be downloaded from the following locations:

Citrix XenServer 7.6: CTX239437 -
https://support.citrix.com/article/CTX239437

Citrix XenServer 7.5: CTX239436 -
https://support.citrix.com/article/CTX239436

Citrix XenServer 7.1 LTSR CU1: CTX239435 -
https://support.citrix.com/article/
CTX239435

Citrix XenServer 7.0: CTX239434 -
https://support.citrix.com/article/CTX239434



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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/.

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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.

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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

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Changelog

+--------------------------------+--------------------------------------------+
|Date                            |Change
     |
+--------------------------------+--------------------------------------------+
|20th November 2018              |Initial Issue
     |
+--------------------------------+--------------------------------------------+


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+ 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   +
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