Vulmon
Description of Problem
Several 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. In addition, unprivileged code in a PV guest VM may be able to cause that guest VM to crash.
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-2020-25595
- CVE-2020-25596
- CVE-2020-25597
- CVE-2020-25599
- CVE-2020-25600
- CVE-2020-25601
- CVE-2020-25602
- CVE-2020-25603
- CVE-2020-25604
Mitigating Factors
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: XS82E007 – https://support.citrix.com/article/CTX283446
Citrix Hypervisor 8.1: XS81E009 – https://support.citrix.com/article/CTX283445
Citrix XenServer 7.1 LTSR CU2: XS71ECU2047 – https://support.citrix.com/article/CTX283444
Citrix XenServer 7.0: XS70E083 – https://support.citrix.com/article/CTX283443
A previous version of this bulletin had links to hotfixes that addressed the security issues but caused stability issues for some deployments that were using the Hypervisor Introspection (HVI) functionality of Citrix Hypervisor. Customers who are not using HVI functionality and who have already applied the earlier updates need take no further action.
Acknowledgements
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/.
To receive future security bulletins, customers can update their support notifications at https://support.citrix.com/user/alerts or subscribe to the RSS feed at https://support.citrix.com/feeds.
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.html.
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
Changelog
| Date | Change |
| 2020-09-22 | Initial Publication |
| 2020-10-09 | Hotfix Update |