---
id: CVE-2017-6679
title: >-
  The Cisco Umbrella Virtual Appliance Version 2.0.3 and prior contained an
  undocumented encrypted remote support tunnel (SSH) which auto initiated from
  the customer's appliance to Cisco's SSH Hubs in the Umbrella datacenters
summary: >-
  The Cisco Umbrella Virtual Appliance Version 2.0.3 and prior contained an
  undocumented encrypted remote support tunnel (SSH) which auto initiated from
  the customer's appliance to Cisco's SSH Hubs in the Umbrella datacenters.
  These tunnel…
severity: medium
cvss: 6.4
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H'
published: '2017-12-01'
updated: '2026-06-22'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2017-6679'
references:
  - url: 'http://www.securityfocus.com/bid/101567'
    label: psirt@cisco.com
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-umbrella-tunnel-gJw5thgE
    label: psirt@cisco.com
  - url: 'https://support.umbrella.com/hc/en-us/articles/115004154423'
    label: psirt@cisco.com
  - url: >-
      https://support.umbrella.com/hc/en-us/articles/115004752143-Virtual-Appliance-Vulnerability-due-to-always-on-SSH-Tunnel-RESOLVED-2017-09-15
    label: psirt@cisco.com
  - url: 'https://www.info-sec.ca/advisories/Cisco-Umbrella.html'
    label: psirt@cisco.com
  - url: 'http://www.securityfocus.com/bid/101567'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-umbrella-tunnel-gJw5thgE
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://support.umbrella.com/hc/en-us/articles/115004154423'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://support.umbrella.com/hc/en-us/articles/115004752143-Virtual-Appliance-Vulnerability-due-to-always-on-SSH-Tunnel-RESOLVED-2017-09-15
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.info-sec.ca/advisories/Cisco-Umbrella.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00338
epssPercentile: 0.2722
ingestedAt: '2026-06-29T13:24:33.209Z'
---

## Overview

The Cisco Umbrella Virtual Appliance Version 2.0.3 and prior contained an undocumented encrypted remote support tunnel (SSH) which auto initiated from the customer's appliance to Cisco's SSH Hubs in the Umbrella datacenters. These tunnels were primarily leveraged for remote support and allowed for authorized/authenticated personnel from the Cisco Umbrella team to access the appliance remotely and obtain full control without explicit customer approval. To address this vulnerability, the Umbrella Virtual Appliance version 2.1.0 now requires explicit customer approval before an SSH tunnel from the VA to the Cisco terminating server can be established.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.