Description of Problem

Several security issues have been identified that, collectively, may allow privileged code running in a guest VM to compromise the host or cause a denial of service.

These vulnerabilities have the following identifiers: 

CVE ID	Description	Vulnerability Type	Pre-conditions
CVE-2020-29479	An attacker with the ability to execute privileged mode code in a guest can compromise the host	CWE-707: Improper Neutralization	Administrator access in guest
CVE-2020-29480	An attacker with the ability to execute privileged mode code in a guest can read non-sensitive metadata about another guest	CWE-284: Improper Access Control	Administrator access in guest
CVE-2020-29481	An attacker with the ability to execute privileged mode code in a guest can read data previously shared, using the Xenstore API, between two other guests	CWE-664: Improper Control of a Resource Through its Lifetime	Administrator access in guest
CVE-2020-29482	An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host	CWE-664: Improper Control of a Resource Through its Lifetime	Administrator access in guest
CVE-2020-29485	An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host	CWE-664: Improper Control of a Resource Through its Lifetime	Administrator access in guest
CVE-2020-29486	An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host or a selected other VM	CWE-664: Improper Control of a Resource Through its Lifetime	Administrator access in guest
CVE-2020-29487	An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host	CWE-664: Improper Control of a Resource Through its Lifetime	Administrator access in guest
CVE-2020-29568	An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host	CWE-664: Improper Control of a Resource Through its Lifetime	Administrator access in guest
CVE-2020-29569	An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host	CWE-664: Improper Control of a Resource Through its Lifetime	Administrator access in guest
CVE-2020-29570	An attacker with the ability to execute privileged mode code in a guest can perform a denial of service attack against the host	CWE-664: Improper Control of a Resource Through its Lifetime	Administrator access in guest

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 soon as practicable.  The hotfixes can be downloaded from the following locations:

Citrix Hypervisor 8.2 LTSR:
CTX286796 – https://support.citrix.com/article/CTX286796 and
CTX286800 – https://support.citrix.com/article/CTX286800 and
CTX286804 – https://support.citrix.com/article/CTX286804

Citrix Hypervisor 8.1:
CTX286795 – https://support.citrix.com/article/CTX286795 and
CTX286799 – https://support.citrix.com/article/CTX286799 and
CTX286803 – https://support.citrix.com/article/CTX286803

Citrix XenServer 7.1 LTSR CU2:
CTX286794 – https://support.citrix.com/article/CTX286794 and
CTX286798 – https://support.citrix.com/article/CTX286798 and
CTX286802 – https://support.citrix.com/article/CTX286802

Citrix XenServer 7.0:
CTX286793 – https://support.citrix.com/article/CTX286793 and
CTX286797 – https://support.citrix.com/article/CTX286797 and
CTX286801 – https://support.citrix.com/article/CTX286801
 

What Citrix Is Doing

Citrix is notifying customers and channel partners about this potential security issue. This article is also available from the Citrix Knowledge Center at http://support.citrix.com/.
 

Obtaining Support on This Issue

If you require technical assistance with this issue, please contact Citrix Technical Support. Contact details for Citrix Technical Support are available at http://www.citrix.com/site/ss/supportContacts.asp.
 

Reporting Security Vulnerabilities

Citrix welcomes input regarding the security of its products and considers any and all potential vulnerabilities seriously. For details on our vulnerability response process and guidance on how to report security-related issues to Citrix, please see the following webpage: – https://www.citrix.com/about/trust-center/vulnerability-process.html
 

Disclaimer

This document is provided on an "as is" basis and does not imply any kind of guarantee or warranty, including the warranties of merchantability or fitness for a particular use. Your use of the information on the document is at your own risk. Citrix reserves the right to change or update this document at any time.
 

Changelog

Date	Change
2020-12-15	Initial Publication