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             AUSCERT External Security Bulletin Redistribution

                     Citrix Hypervisor Security Update
                             12 November 2020


        AusCERT Security Bulletin Summary

Product:           Citrix Hypervisor (formerly Citrix Xenserver)
Publisher:         Citrix
Operating System:  Citrix XenServer
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
                   Increased Privileges            -- Existing Account
                   Denial of Service               -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-27675 CVE-2020-27674 CVE-2020-27673
                   CVE-2020-27672 CVE-2020-27671 CVE-2020-27670

Reference:         ESB-2020.3761

Original Bulletin: 

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Citrix Hypervisor Security Update

Reference: CTX284874

Category : Medium

Created  : 27 Oct 2020

Modified : 27 Oct 2020

Applicable Products

  o Citrix Hypervisor
  o XenServer

Description of Problem

Several security issues have been identified in Citrix Hypervisor (formerly
Citrix XenServer) that may allow:

  o unprivileged code in a PV guest VM to compromise that PV guest VM
  o privileged code in a guest VM to cause the host to crash or become
  o privileged code in an HVM guest VM, to which the host administrator has
    assigned a PCI passthrough device, to corrupt in-memory data of the host or
    other VMs and potentially cause the host to crash.

These issues have the following identifiers:

  o CVE-2020-27670
  o CVE-2020-27671
  o CVE-2020-27672
  o CVE-2020-27673
  o CVE-2020-27674
  o CVE-2020-27675

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

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: CTX283510 - https://support.citrix.com/article/
CTX283510 and CTX283516 - https://support.citrix.com/article/CTX283516

Citrix Hypervisor 8.1: CTX283509 - https://support.citrix.com/article/CTX283509
and CTX283515 - https://support.citrix.com/article/CTX283515

Citrix XenServer 7.1 LTSR CU2: CTX283508 - https://support.citrix.com/article/
CTX283508 and CTX283514 - https://support.citrix.com/article/CTX283514

Citrix XenServer 7.0: CTX283507 - https://support.citrix.com/article/CTX283507 
and CTX283512 - https://support.citrix.com/article/CTX283512


|Date                 |Change                                                 |
|2020-10-27           |Initial Publication                                    |
|2020-10-27           |Corrected links to hotfixes                            |

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