CVE-2018-3665 - Citrix XenServer Security Update

Description of Problem

An issue has been identified in certain CPUs that may allow code running in a guest VM to read data from another process in the same VM or another VM running on the same host. The data that can be read is limited to specific CPU registers rather than memory or disk storage; however, those registers may contain sensitive information.

This issue affects all currently supported versions of Citrix XenServer up to and including Citrix XenServer 7.5.

The following issue has been addressed:

• CVE-2018-3665: Speculative register leakage from lazy FPU context switching

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Mitigating Factors

Customers with AMD-based CPUs are believed to be unaffected by this issue.

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What Customers Should Do

Hotfixes have been released to mitigate these issues. Citrix recommends that affected customers install these hotfixes. The hotfixes can be downloaded from the following locations:

Citrix XenServer 7.5: CTX235135 – <https://support.citrix.com/article/CTX235135&gt;

Citrix XenServer 7.4: CTX235175 – <https://support.citrix.com/article/CTX235175&gt;

Citrix XenServer 7.3: CTX235956 – <https://support.citrix.com/article/CTX235956&gt;

Citrix XenServer 7.1 LTSR CU1: CTX235957 – <https://support.citrix.com/article/CTX235957&gt;

Citrix XenServer 7.0: CTX235958 – <https://support.citrix.com/article/CTX235958&gt;

Citrix recommends that customers follow the guidance of their operating system vendors for updates to the operating systems of their guest VMs.

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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/&gt;_.

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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&gt;_.

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Reporting Security Vulnerabilities

Citrix welcomes input regarding the security of its products and considers any and all potential vulnerabilities seriously. For guidance on how to report security-related issues to Citrix, please see the following document: CTX081743 – Reporting Security Issues to Citrix

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Changelog

Date	Change
15th June 2018	Initial Issue

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