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             AUSCERT External Security Bulletin Redistribution

                     Citrix Hypervisor Security Update
                              12 October 2020


        AusCERT Security Bulletin Summary

Product:           Citrix Hypervisor
Publisher:         Citrix
Operating System:  Citrix XenServer
Impact/Access:     Increased Privileges     -- Existing Account
                   Denial of Service        -- Existing Account
                   Access Confidential Data -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-25604 CVE-2020-25603 CVE-2020-25602
                   CVE-2020-25601 CVE-2020-25600 CVE-2020-25599
                   CVE-2020-25597 CVE-2020-25596 CVE-2020-25595

Reference:         ESB-2020.3251

Original Bulletin: 

Revision History:  October   12 2020: Hotfix Update
                   September 24 2020: Initial Release

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Citrix Hypervisor Security Update

Reference: CTX282314

Category : Medium

Created  : 23 Sep 2020

Modified : 09 Oct 2020

Applicable Products

  o Citrix Hypervisor
  o XenServer 7.1
  o XenServer 7.0

Description of Problem

Several security issues have been identified in Citrix Hypervisor (formerly
Citrix XenServer) that may allow privileged code in a guest VM to cause the
host to crash or become unresponsive. In addition, unprivileged code in a PV
guest VM may be able to cause that guest VM to crash.

These issues affect all currently supported versions of Citrix Hypervisor up to
and including Citrix Hypervisor 8.2 LTSR.

These issues have the following identifiers:

  o CVE-2020-25595
  o CVE-2020-25596
  o CVE-2020-25597
  o CVE-2020-25599
  o CVE-2020-25600
  o CVE-2020-25601
  o CVE-2020-25602
  o CVE-2020-25603
  o CVE-2020-25604

Mitigating Factors

What Customers Should Do

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

Citrix Hypervisor 8.2 LTSR:XS82E007 - https://support.citrix.com/article/

Citrix Hypervisor 8.1:XS81E009 - https://support.citrix.com/article/CTX283445

Citrix XenServer 7.1 LTSR CU2:XS71ECU2047 - https://support.citrix.com/article/

Citrix XenServer 7.0:XS70E083 - https://support.citrix.com/article/CTX283443

A previous version of this bulletin had links to hotfixes that addressed
thesecurityissues but caused stability issues for some deployments that were
using the Hypervisor Introspection (HVI) functionality of Citrix Hypervisor.
Customers who are not using HVI functionality and who have already applied the
earlier updates need take no further action.



|Date                      |Change                                            |
|2020-09-22                |Initial Publication                               |
|2020-10-09                |Hotfix Update                                     |

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