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                             CERT-Renater

                 Note d'Information No. 2021/VULN193
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DATE                : 01/04/2021

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running Citrix Hypervisor version up to and
                            including Citrix Hypervisor 8.2 LTSR.

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https://support.citrix.com/article/CTX306565
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CTX306565
Citrix Hypervisor Security Update

Security Bulletin | Medium | 3 found this helpful | Created: 30 Mar 2021
| Modified: 30 Mar 2021


Applicable Products

    Citrix Hypervisor


Description of Problem

Two security issues have been identified in Citrix Hypervisor (formerly
Citrix XenServer) that may allow privileged code in a guest VM to cause
the host to crash or become unresponsive.

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


These issues have the following identifiers:

CVE ID 	Description 	Type 	Pre-requisites
CVE-2021-28038 	An attacker with the ability to execute privileged mode
code in a guest can perform a denial of service attack against the
host 	CWE-400: Uncontrolled Resource Consumption 	Ability to run
privileged code in a guest VM

CVE-2021-28688 	An attacker with the ability to execute privileged mode
code in a guest can perform a denial of service attack against the
host 	CWE-400: Uncontrolled Resource Consumption 	Ability to run
privileged code in a guest VM


An additional issue has been identified in Citrix Hypervisor 8.2 LTSR
(only) that may allow malicious network traffic to cause subsequent
packets to be dropped.


This issue has the following identifier:

CVE ID 	Description 	Type 	Pre-requisites
CVE-2020-35498 	Malicious network traffic on the local network may cause
subsequent packets to be dropped 	CWE-682: Incorrect Calculation 	Access
to the local network


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: CTX306481 –
https://support.citrix.com/article/CTX306481 and CTX306423 –
https://support.citrix.com/article/CTX306423
Citrix XenServer 7.1 LTSR CU2: CTX306480 –
https://support.citrix.com/article/CTX306480
Citrix XenServer 7.0: CTX306482 –
https://support.citrix.com/article/CTX306482


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 to Citrix
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
2021-03-30      Initial Publication


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+ CERT-RENATER       |    tel : 01-53-94-20-44          +
+ 23/25 Rue Daviel   |    fax : 01-53-94-20-41          +
+ 75013 Paris        |    email:cert@support.renater.fr +
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