Cisco Security Advisory
Cisco Umbrella Virtual Appliance Undocumented Support Tunnel Vulnerability
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CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
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A vulnerability in the remote support feature of Cisco Umbrella Virtual Appliance could allow an authenticated, remote attacker to obtain full control of an affected device.
This vulnerability is due to an undocumented support mechanism that is present on the product. An attacker could exploit this vulnerability by obtaining privileges sufficient to access the remote support tunnel. A successful exploit could allow the attacker to access the appliance remotely and obtain full control without explicit customer approval.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Cisco Umbrella originally published this advisory in 2017 on a different site that has since been archived.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-umbrella-tunnel-gJw5thgE
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Vulnerable Products
At the time of publication, this vulnerability affected Cisco Umbrella Virtual Appliances.
For information about which Cisco software releases were vulnerable at the time of publication, see the Fixed Software section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
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The Cisco Umbrella Virtual Appliance releases 2.0.3 and earlier contained an undocumented encrypted remote support tunnel (SSH) which auto initiated from customer appliances to Cisco SSH Hubs in the Umbrella data centers. These tunnels were primarily leveraged for remote support and allowed for authorized and authenticated personnel from the Cisco Umbrella team to access the appliance remotely and obtain full control without explicit customer approval. To address this vulnerability, Cisco Umbrella Virtual Appliance Release 2.1.0 now requires explicit customer approval before an SSH tunnel from the virtual appliance to the Cisco terminating server can be established.
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There are no workarounds that address this vulnerability.
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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.
Fixed Releases
At the time of publication, the release information in the following table(s) was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
The left column lists Cisco software releases, and the right column indicates whether a release was affected by the vulnerability that is described in this advisory and which release included the fix for this vulnerability.
Cisco Umbrella Virtual Appliance Release First Fixed Release 2.0.3 and earlier 2.1.0 The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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Cisco would like to thank David Coomber for reporting this vulnerability.
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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.
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Show LessVersion Description Section Status Date 1.0 Initial public release. - Final 2023-AUG-16
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