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AUSCERT External Security Bulletin Redistribution
ESB-2020.3579
VMSA-2020-0022 - VMware Horizon Client update addresses a
denial-of-service vulnerability (CVE-2020-3991)
19 October 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: VMware Horizon Client for Windows
Publisher: VMWare
Operating System: VMware ESX Server
Virtualisation
Impact/Access: Overwrite Arbitrary Files -- Existing Account
Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2020-3991
Original Bulletin:
https://www.vmware.com/security/advisories/VMSA-2020-0022.html
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Advisory ID: VMSA-2020-0022
CVSSv3 Range: 5.9
Issue Date: 2020-10-15
Updated On: 2020-10-15 (Initial Advisory)
CVE(s): CVE-2020-3991
Synopsis: VMware Horizon Client update addresses a denial-of-service
vulnerability (CVE-2020-3991)
1. Impacted Products
o VMware Horizon Client for Windows
2. Introduction
A denial-of-service vulnerability affecting VMware Horizon Client for
Windows was privately reported to VMware. Updates are available to address this
vulnerability in affected VMware product.
3. File system access control denial-of-service vulnerability (CVE-2020-3991)
Description
VMware Horizon Client for Windows contains a denial-of-service vulnerability
due to a file system access control issue during install time. VMware has
evaluated the severity of this issue to be in the Moderate severity range with
a maximum CVSSv3 base score of 5.9.
Known Attack Vectors
Successful exploitation of this issue may allow an attacker to overwrite
certain admin privileged files through a symbolic link attack at install time.
This will result into a denial-of-service condition on the machine where
Horizon Client for Windows is installed.
Resolution
To remediate CVE-2020-3991 apply the patches listed in the 'Fixed Version'
column of the 'Response Matrix' below.
Workarounds
None.
Additional Documentation
None.
Notes
None.
Acknowledgements
VMware would like to thank Eran Shimony of CyberArk for reporting this issue to
us.
Response Matrix
Product Version Running CVE CVSSv3 Severity Fixed Workarounds Additional
On Identifier Version Documentation
Horizon
Client 5.x and Windows CVE-2020-3991 5.9 moderate 5.5.0 None None
for prior
Windows
4. References
Fixed Version(s) and Release Notes:
Horizon Client for Windows 5.5.0
Downloads and Documentation:
https://my.vmware.com/en/web/vmware/downloads/details?downloadGroup=CART21FQ3_WIN_550&productId=863&rPId=53321
https://docs.vmware.com/en/VMware-Horizon-Client/index.html
Mitre CVE Dictionary Links:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-3991
FIRST CVSSv3 Calculator:
https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:H
5. Change Log
2020-10-15 VMSA-2020-0022
Initial security advisory.
6. Contact
E-mail list for product security notifications and announcements:
https://lists.vmware.com/cgi-bin/mailman/listinfo/security-announce
This Security Advisory is posted to the following lists:
security-announce@lists.vmware.com
E-mail: security@vmware.com
PGP key at:
https://kb.vmware.com/kb/1055
VMware Security Advisories
https://www.vmware.com/security/advisories
VMware Security Response Policy
https://www.vmware.com/support/policies/security_response.html
VMware Lifecycle Support Phases
https://www.vmware.com/support/policies/lifecycle.html
VMware Security & Compliance Blog
https://blogs.vmware.com/security
Twitter
https://twitter.com/VMwareSRC
Copyright 2020 VMware Inc. All rights reserved.
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