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                                CERT-Renater

                      Note d'Information No. 2023/VULN396

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DATE                : 12/10/2023

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running Citrix Hypervisor versions
                                      8.2 CU1 LTSR.

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https://support.citrix.com/article/CTX575089/citrix-hypervisor-multiple-security-updates
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CTX575089
Citrix Hypervisor Multiple Security Updates
Security Bulletin | Severity: High | Created: 10 Oct 2023 |
Modified: 10 Oct 2023 | Status: Final
Applicable Products

     Citrix Hypervisor XenServer

Description of Problem

Several issues have been discovered that affect Citrix Hypervisor
8.2 CU1 LTSR and may allow malicious privileged code in a guest VM
to:

i)  Compromise an AMD-based host via a passed through PCI device:
CVE-2023-34326
ii)  Compromise the host when a specific administrative action is
taken (see Mitigating Factors below): CVE-2022-1304
iii)  Cause the host to crash or become unresponsive: CVE-2023-34324
iv)  Cause a different VM running on the AMD-based host to crash:
CVE-2023-34327

In addition, AMD has disclosed a security issue affecting certain
AMD CPUs. Although this is not an issue in the Citrix Hypervisor
product itself, we have included the AMD recommended product changes
to mitigate this CPU hardware issue. This issue may allow code in
a guest VM to determine values from previous integer divides in
code running on the same CPU core: CVE-2023-20588

Collectively, these issues have the following identifiers:

     CVE-2022-1304
     CVE-2023-20588
     CVE-2023-34324
     CVE-2023-34326
     CVE-2023-34327

  Mitigating Factors
CVE-2023-34326 only affects systems that have both of a) a PCI device
passed through to the guest VM by the host administrator and
also b) an AMD CPU. Customers who are not using AMD CPUs and
customers who are not using the PCI passthrough feature are not
affected by this issue.

CVE-2022-1304 is only exploitable at the point that the host
administrator uses the “Restore Virtual Machine Metatdata”
sub-option of the “Backup, Restore and Update” menu item in
the on-host xsconsole interface. Customers who do not use this
sub-option are not affected by this issue.

CVE-2023-34327 only affects systems running on AMD CPUs.
Customers who are not using AMD CPUs are not affected by
this issue.

CVE-2023-20588 only affects systems running on AMD Zen1
CPUs. Customers who are using other generations of AMD
CPUs or who are not using AMD CPUs are not affected by
this issue.

  What Customers Should Do

We have released hotfixes to address these issues. We
recommend that affected customers install these hotfixes
and follow the instructions in the linked articles as
their update schedule permits. The hotfixes can be
downloaded from the following locations:

CTX575070 - https://support.citrix.com/article/CTX575070
CTX579955 - https://support.citrix.com/article/CTX579955
CTX580401 - https://support.citrix.com/article/CTX580401
CTX581053 - https://support.citrix.com/article/CTX581053
CTX581108 - https://support.citrix.com/article/CTX581108

Note that there is not a one-to-one correlation between these
hotfixes and the addressed issues; we recommend that you
always apply all of the hotfixes.

  What Citrix Is Doing

We are notifying customers and channel partners about this
potential security issue through the publication of this
security bulletin on the Citrix Knowledge Center at
https://support.citrix.com/securitybulletins.

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.

  Subscribe to Receive Alerts
Citrix strongly recommends that all customers subscribe to
receive alerts when a Citrix security bulletin is created or
modified at https://support.citrix.com/user/alerts.

Reporting Security Vulnerabilities to Citrix
Citrix welcomes input regarding the security of its products
and considers any and all potential vulnerabilities seriously.
For details on our vulnerability response process and guidance
on how to report security-related issues to Citrix, please
see the following webpage:
https://www.citrix.com/about/trust-center/vulnerability-process.html.
  Disclaimer
This document is provided on an "as is" basis and does not
imply any kind of guarantee or warranty, including the
warranties of merchantability or fitness for a particular
use. Your use of the information on the document is at your
own risk. Citrix reserves the right to change or update
this document at any time. Customers are therefore
recommended to always view the latest version of this
document directly from the Citrix Knowledge Center.

Changelog

  Date 	         Change
  2023-10-10      Initial Publication  2023-10-10      Corrected Hyperlinks

=========================================================
+ 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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