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AUSCERT External Security Bulletin Redistribution
ESB-2019.4056
Hypervisor Security Update
1 November 2019
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AusCERT Security Bulletin Summary
---------------------------------
Product: Citrix Hypervisor
Publisher: Citrix
Operating System: Citrix XenServer
Impact/Access: Increased Privileges -- Existing Account
Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2019-18425 CVE-2019-18424 CVE-2019-18421
CVE-2019-18420
Original Bulletin:
https://support.citrix.com/article/CTX263477
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Hypervisor Security Update
Reference: CTX263477
Category : High
Created : 31 Oct 2019
Modified : 31 Oct 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 allow the host to be compromised by:
i. Privileged code in a guest VM that has been assigned a PCI passthrough
device
ii. Privileged code in a PV guest VM
iii. Unprivileged code in a 32-bit PV guest VM
These vulnerabilities have the following identifiers:
o CVE-2019-18420
o CVE-2019-18421
o CVE-2019-18424
o CVE-2019-18425
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 and not making use of PCI passthrough
functionality are not affected by these issues. Note that all Microsoft Windows
VMs run as HVM VMs.
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:
CTX262555 - https://support.citrix.com/article/CTX262555
CTX258428 - https://support.citrix.com/article/CTX258428
Citrix XenServer 7.6:
CTX262554 - https://support.citrix.com/article/CTX262554
CTX258425 - https://support.citrix.com/article/CTX258425
Citrix XenServer 7.1 LTSR CU2:
CTX262553 - https://support.citrix.com/article/CTX262553
CTX258424 - https://support.citrix.com/article/CTX258424
Citrix XenServer 7.0:
CTX258417 - https://support.citrix.com/article/CTX258417
CTX258423 - https://support.citrix.com/article/CTX258423
Changelog
+------------------------------------+----------------------------------------+
|Date |Change |
+------------------------------------+----------------------------------------+
|31st October 2019 |Initial publication |
+------------------------------------+----------------------------------------+
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===========================================================================
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