Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.3026 Citrix Hypervisor Security Update 9 September 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Citrix Hypervisor Publisher: Citrix Operating System: Virtualisation Impact/Access: Execute Arbitrary Code/Commands -- Existing Account Denial of Service -- Existing Account Access Confidential Data -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2021-28701 CVE-2021-28699 CVE-2021-28698 CVE-2021-28697 CVE-2021-28696 CVE-2021-28695 CVE-2021-28694 Reference: ESB-2021.3023 ESB-2021.2998 ESB-2021.2987 Original Bulletin: https://support.citrix.com/article/CTX325319 - --------------------------BEGIN INCLUDED TEXT-------------------- Citrix Hypervisor Security Update Reference: CTX325319 Category : High Created : 07 September 2021 Modified : 08 September 2021 Applicable Products o Citrix Hypervisor Description of Problem Several security issues have been discovered in Citrix Hypervisor that, collectively, may allow privileged code in a guest VM to compromise or crash the host. These issues have the following identifiers: +--------------+-----------+--------------------------------------------------+ |CVE-ID |Description|Pre-requisites | +--------------+-----------+--------------------------------------------------+ | | |Malicious privileged code execution in a guest VM | | | |running on a host with firmware that declares ACPI| |CVE-2021-28694|Host denial|tables which includes memory regions that are | | |of service |identity mapped for devices that have been | | | |explicitly assigned, by the host administrator, to| | | |that guest VM in PCI passthrough mode. | +--------------+-----------+--------------------------------------------------+ |CVE-2021-28697|Host |Malicious privileged code execution in a guest VM | | |compromise |that has two or more vCPUs allocated to it | +--------------+-----------+--------------------------------------------------+ |CVE-2021-28698|Host denial|Malicious privileged code execution in a guest VM | | |of service | | +--------------+-----------+--------------------------------------------------+ | |Host |Malicious privileged code execution in a guest VM | |CVE-2021-28699|compromise |on a host where the host administrator has | | | |modified the guest or host grant table limits | +--------------+-----------+--------------------------------------------------+ |CVE-2021-28701|Host |Malicious privileged code execution in a guest VM | | |compromise |that has two or more vCPUs allocated to it | +--------------+-----------+--------------------------------------------------+ All currently supported versions of Citrix Hypervisor are affected by all of these issues with the exception of CVE-2021-28699 which only affects 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: CTX324257 - https://support.citrix.com/article/ CTX324257 Citrix Hypervisor 7.1 LTSR CU2: CTX324256 - https://support.citrix.com/article/ CTX324256 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 https://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 https://www.citrix.com/support/open-a-support-case/ . 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. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBYTl77eNLKJtyKPYoAQhHHRAAlvf+S6NjjgtUKe3Il//bBmdF/7QTxFPS CajjrersjhzzQI+9Li3aiFHgwiNABGJI4AENwBLOwE9jh74CqR0IND3EEbVwS0dT PfAM++TDV8EJavnQ9/hQXtPhrWRMLfKR1Izz78p63rLUxB/dgAWPpvROIL9w3mX/ uTIypxV0RYUJp45SxMawZjNdPNjTMBZ8zBavmGH/rLoJ6KzdZfl6xkfUKE85hNFp HziePew9x/tBFb1Idt+RUF1LWtn+EDvKX2nd4gPQKg4aKYwVEz2Ic2hdVOVoWRWH Sow0cvKjBe6XOg9ydWKbPGxG39Imu3halo2lhiqozoQxWpQx8A3uYmxidhBQyc4/ lSkPcGm1VyEeR2MkiQAYxB+rGNUkvU7KgEts6/5SMiTUYddFPKmRAA7fwmUYoIqE STY1QknfXWI2iduoEsnbJZS/fREY+r/Il1EoYVsulMTRXac21UGl96ekYQ5eqIJL YCtm3x8/P844YV7+LUUIgJi82GBEF81FiVl/tbk44P8wfafD35SFI7AApipdOgwv NBmLnAlcLXa/GgTJKBLjeUCpguv2/W55y0AEPC9YVl1KYrVILf4ZOye9wEukM7cw POgymaVEWBLK29qH5UAFx3r1skZH2ysaKxKAwjALSmPmdBK/HhKdxtsG21iuAbzv iG1nuDDyYls= =6QKL -----END PGP SIGNATURE-----