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AUSCERT External Security Bulletin Redistribution
ESB-2022.1726
Cisco Umbrella Virtual Appliance Static SSH Host Key Vulnerability
21 April 2022
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AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco Umbrella Virtual Appliance
Publisher: Cisco Systems
Operating System: Virtualisation
Resolution: Patch/Upgrade
CVE Names: CVE-2022-20773
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-uva-static-key-6RQTRs4c
Comment: CVSS (Max): 7.5 CVE-2022-20773 (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H)
CVSS Source: Cisco Systems
Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
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Cisco Umbrella Virtual Appliance Static SSH Host Key Vulnerability
Priority: High
Advisory ID: cisco-sa-uva-static-key-6RQTRs4c
First Published: 2022 April 20 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCwa11399
CVE Names: CVE-2022-20773
CWEs: CWE-321
Summary
o A vulnerability in the key-based SSH authentication mechanism of Cisco
Umbrella Virtual Appliance (VA) could allow an unauthenticated, remote
attacker to impersonate a VA.
This vulnerability is due to the presence of a static SSH host key. An
attacker could exploit this vulnerability by performing a man-in-the-middle
attack on an SSH connection to the Umbrella VA. A successful exploit could
allow the attacker to learn the administrator credentials, change
configurations, or reload the VA.
Note : SSH is not enabled by default on the Umbrella VA.
Cisco has released software updates that address this vulnerability. There
are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-uva-static-key-6RQTRs4c
Affected Products
o Vulnerable Products
This vulnerability affects the Cisco Umbrella Virtual Appliance for both
VMWare ESXi and Hyper-V running a software version earlier than 3.3.2.
Determine the Software Version
The version of the VA is verified by opening the VA in the hypervisor
console or navigating to the Umbrella Dashboard as follows:
Deployments > Configuration > Sites and Active Directory
To determine if SSH is enabled, log in to the hypervisor console, enter
configuration mode by pressing CTRL+B , and enter the command config va
show .
The following example shows the output of the config va show command for a
device that has SSH enabled:
~ $ config va show
Virtual Appliance Configuration
Name:
Local DNS -
ip address :
DNSSEC : disabled
Internal Domains Count: 0
Resolvers: 208.67.220.220 208.67.222.222
SSH access : enabled
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Workarounds
o There are no workarounds that address this vulnerability.
Fixed Software
o Cisco has released free software updates that address the vulnerability
described in this advisory. Customers with service contracts that entitle
them to regular software updates should obtain security fixes through their
usual update channels.
Customers may only install and expect support for software versions and
feature sets for which they have purchased a license. By installing,
downloading, accessing, or otherwise using such software upgrades,
customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.html
Additionally, customers may only download software for which they have a
valid license, procured from Cisco directly, or through a Cisco authorized
reseller or partner. In most cases this will be a maintenance upgrade to
software that was previously purchased. Free security software updates do
not entitle customers to a new software license, additional software
feature sets, or major revision upgrades.
The Cisco Support and Downloads page on Cisco.com provides information
about licensing and downloads. This page can also display customer device
support coverage for customers who use the My Devices tool.
When considering software upgrades , customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories page , to determine exposure and a complete
upgrade solution.
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service
contract and customers who make purchases through third-party vendors but
are unsuccessful in obtaining fixed software through their point of sale
should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c
/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared
to provide the URL of this advisory as evidence of entitlement to a free
upgrade.
Fixed Releases
Customers are advised to upgrade to an appropriate fixed software release
as indicated in the following table(s):
Cisco Umbrella Virtual Appliance Software First Fixed Release
Release
3.2 and earlier Migrate to a fixed
release.
3.3 3.3.2
The Cisco Product Security Incident Response Team (PSIRT) validates only
the affected and fixed release information that is documented in this
advisory.
Exploitation and Public Announcements
o The Cisco PSIRT is not aware of any public announcements or malicious use
of the vulnerability that is described in this advisory.
Source
o Cisco would like to thank Fraser Hess of Pinnacol Assurance for reporting
this vulnerability.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy . This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-uva-static-key-6RQTRs4c
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2022-APR-20 |
+----------+---------------------------+----------+--------+--------------+
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