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AUSCERT External Security Bulletin Redistribution
ESB-2018.0819
Citrix XenServer Multiple Security Updates
22 March 2018
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AusCERT Security Bulletin Summary
---------------------------------
Product: Citrix XenServer
Publisher: Citrix
Operating System: Citrix XenServer
Linux variants
BSD variants
Impact/Access: Execute Arbitrary Code/Commands -- Existing Account
Increased Privileges -- Existing Account
Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2018-7541 CVE-2018-7540 CVE-2016-2074
Reference: ESB-2018.0772
ESB-2018.0651
ESB-2016.0815
ESB-2016.0811
Original Bulletin:
https://support.citrix.com/article/CTX232655
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Citrix XenServer Multiple Security Updates
Security Bulletin | Critical
| Created: 21 Mar 2018 | Modified: 21 Mar 2018
Applicable Products
o XenServer 7.3
o XenServer 7.2
o XenServer 7.1 LTSR Cumulative Update 1
o XenServer 7.0
Description of Problem
A number of vulnerabilities have been identified within Citrix XenServer that
could, if exploited, allow a malicious administrator of a guest VM to crash the
host and, for some XenServer versions, allow a remote attacker to compromise
the host.
The following vulnerabilities have been addressed:
o CVE-2016-2074: openvswitch: MPLS buffer overflow vulnerability
o CVE-2018-7540: DoS via non-preemptable L3/L4 pagetable freeing
o CVE-2018-7541: grant table v2 -> v1 transition may crash Xen
The host compromise issue (CVE-2016-2074) affects Citrix XenServer versions 7.0
and 7.1 CU1 only.
The denial of service issues affect all supported versions of Citrix XenServer
prior to version 7.4.
Mitigating Factors
Customers using the "Linux bridge" networking mode are unaffected by the host
compromise issue.
What Customers Should Do
Hotfixes have been released to address these issues. Citrix strongly recommends
that affected customers install these hotfixes as soon as possible. The
hotfixes can be downloaded from the following locations:
Citrix XenServer 7.3: CTX233368 - https://support.citrix.com/article/CTX233368
Citrix XenServer 7.2: CTX233366 - https://support.citrix.com/article/CTX233366
Citrix XenServer 7.1 LTSR CU1: CTX233363 - https://support.citrix.com/article/
CTX233363 and CTX233365 - https://support.citrix.com/article/CTX233365
Citrix XenServer 7.0: CTX233362 - https://support.citrix.com/article/CTX233362
and CTX233364 - https://support.citrix.com/article/CTX233364
These hotfixes are not livepatchable.
Citrix is actively working on remediating the denial of service issues for
releases that are End of Maintenance but not yet End of Life.
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 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 guidance on how to report
security-related issues to Citrix, please see the following document: CTX081743
- - Reporting Security Issues to Citrix
Changelog
+----------------------------------+------------------------------------------+
|Date |Change |
+----------------------------------+------------------------------------------+
|21st March 2018 |Initial publication |
+----------------------------------+------------------------------------------+
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