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             AUSCERT External Security Bulletin Redistribution

                     Citrix Hypervisor Security Update
                             18 December 2019


        AusCERT Security Bulletin Summary

Product:           Citrix Hypervisor 8.0
Publisher:         Citrix
Operating System:  Virtualisation
Impact/Access:     Increased Privileges     -- Existing Account
                   Denial of Service        -- Existing Account
                   Access Confidential Data -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-19583 CVE-2019-19580 CVE-2019-19577

Reference:         ESB-2019.4656

Original Bulletin: 

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Citrix Hypervisor Security Update

Reference: CTX266932

Category : High

Created  : 11 Dec 2019

Modified : 11 Dec 2019

Applicable Products

  o Citrix Hypervisor 8.0
  o XenServer 7.6
  o XenServer 7.1 LTSR Cumulative Update 2
  o XenServer 7.0

Description of Problem

A number of vulnerabilities have been found in Citrix Hypervisor (formerly
Citrix XenServer) that may:

i. Allow the host to be compromised by privileged code in a PV guest VM,

ii. allow unprivileged code in a HVM guest VM to cause that guest to crash and

iii. under certain conditions, allow an HVM guest VM to cause the host to
eventually run out of memory.

These issues have the following identifiers:

o CVE-2019-19580

o CVE-2019-19583

o CVE-2019-19577

In addition, this hotfix contains updated microcode that addresses an issue in
specific Intel CPU hardware that may allow malicious unprivileged code within a
guest VM to compromise that guest VM.

This issue has the following identifier:

o CVE-2019-14607

These issues affect all currently supported versions of Citrix Hypervisor up to
and including Citrix Hypervisor 8.0.

Mitigating Factors

Customers running only HVM workloads are not affected by the host compromise

Customers who are not running on AMD hardware, or who do not use PCI
Passthrough functionality, are not affected by the memory exhaustion issue.

Not all Intel CPUs are affected by the Intel CPU hardware issue. Details of
which CPUs are affected can be found at: https://www.intel.com/content/www/us/
en/security-center/advisory/intel-sa-00317.html .

What Customers Should Do

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

Citrix Hypervisor 8.0: CTX263620 - https://support.citrix.com/article/CTX263620

Citrix XenServer 7.6: CTX263619 - https://support.citrix.com/article/CTX263619

Citrix XenServer 7.1 LTSR CU2: CTX263618 - https://support.citrix.com/article/

Citrix XenServer 7.0: CTX263617 - https://support.citrix.com/article/CTX263617


|Date                                 |Change                                 |
|11th December 2019                   |Initial Publication                    |

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