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             AUSCERT External Security Bulletin Redistribution

                     Citrix Hypervisor Security Update
                              25 August 2020


        AusCERT Security Bulletin Summary

Product:           Citrix Hypervisor
Operating System:  Citrix XenServer
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account      
                   Increased Privileges            -- Existing Account      
                   Denial of Service               -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-14364 CVE-2018-17958 

Reference:         ESB-2019.3215

Original Bulletin: 

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Citrix Hypervisor Security Update

Reference: CTX280451

Category : High

Created  : 24 Aug 2020

Modified : 24 Aug 2020

Applicable Products

  o Citrix Hypervisor
  o XenServer

Description of Problem

Two issues have been identified in Citrix Hypervisor that may, in certain
configurations, allow privileged code in an HVM guest VM to execute code in the
control domain, potentially compromising the host.

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

These issues have the following identifiers:

  o CVE-2020-14364
  o CVE-2018-17958

Mitigating Factors

For customers who have not assigned PCI passthrough devices to untrustworthy
guests (using the PCI-passthrough functionality of Citrix Hypervisor) the
vulnerability is reduced to executing code within a deprivileged environment
within the control domain.

What Customers Should Do

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

Citrix Hypervisor 8.2 LTSR: CTX280214 - https://support.citrix.com/article/

Citrix Hypervisor 8.1: CTX280213 - https://support.citrix.com/article/CTX280213

Citrix Hypervisor 8.0: CTX280212 - https://support.citrix.com/article/CTX280212

Citrix XenServer 7.1 LTSR CU2: CTX280211 - https://support.citrix.com/article/

Citrix XenServer 7.0: CTX280210 - https://support.citrix.com/article/CTX280210

Once the hotfix has been applied, the affected guest HVM VMs will need to be
restarted or migrated to an updated host to make the remediation effective.

Customers on Citrix Hypervisor 8.0 should be aware that this version will
become End of Life on 31 ^ st August 2020 and that Citrix recommends that
customers upgrade to a newer version.



|Date                      |Change                                            |
|2020-08-24                |Initial Publication                               |

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