Meelogic Atlassian Blog

Confluence Security Advisory – 2019-12-18

Summary of vulnerability

This advisory discloses a medium severity security vulnerability which was introduced in version 6.11.0 of Confluence Server and Confluence Data Center. Versions of Confluence Server and Confluence Data Center affected by this vulnerability:

  • from 6.11.0 before 6.13.10 (fixed in 6.13.10)
  • from 6.14.0 before 6.15.10 (fixed in 6.15.10)
  • from 7.0.1 before 7.0.5 (fixed in 7.0.5)
  • from 7.1.0 before 7.1.2 (fixed in 7.1.2)
  • from 7.2.0-beta1 before 7.2.0 (fixed in 7.2.0)

Atlassian Cloud instances have already been upgraded to a version of Confluence which does not have the issue described on this page.

Customers who have upgraded Confluence Server and Confluence Data Center to version 6.13.10, 6.15.10, 7.0.5, 7.1.2, 7.2.0 or higher are not affected.

Customers who are on any of the affected versions listed above, upgrade your Confluence Server and Confluence Data Center installations immediately to fix this vulnerability.

Atlassian Companion man-in-the-middle

Severity

Atlassian rates the severity level of this vulnerability as moderate, according to the scale published in our Atlassian severity levels. The scale allows us to rank the severity as critical, high, moderate or low.

This is our assessment and you should evaluate its applicability to your own IT environment.

Description

There was a man-in-the-middle (MITM) vulnerability present in the Confluence Previews plugin in Confluence Server and Confluence Data Center. This plugin was used to facilitate communication with the Atlassian Companion application. The Confluence Previews plugin in Confluence Server and Confluence Data Center communicated with the Companion application via the atlassian-domain-for-localhost-connections-only.com domain name, the DNS A record of which points at 127.0.0.1. Additionally, a signed certificate for the domain was publicly distributed with the Companion application. An attacker in the position to control DNS resolution of their victim could carry out a man-in-the-middle (MITM) attack between Confluence Server (or Confluence Data Center) and the atlassian-domain-for-localhost-connections-only.com domain intended to be used with the Companion application. This certificate has been revoked, however, usage of the atlassian-domain-for-localhost-connections-only.com domain name was still present in Confluence Server and Confluence Data Center. An attacker could perform the described attack by denying their victim access to certificate revocation information, and carry out a man-in-the-middle (MITM) attack to observe files being edited using the Companion application and/or modify them, and access some limited user information.

Versions of Confluence Server and Confluence Data Center starting with 6.11.0 before 6.13.10 (the fixed version for 6.13.x, 6.12.x and 6.11.x), from 6.14.0 before 6.15.10 (the fixed version for 6.15.x), from 7.0.1 before 7.0.5 (the fixed version for 7.0.x), from 7.1.0 before 7.1.2 (the fixed version for 7.1.x), and from 7.2.0-beta1 before 7.2.0 (the fixed version for 7.2.x) are affected by this vulnerability. This issue can be tracked here:  CONFSERVER-59244 Confluence Server and Data Center – Atlassian Companion Man-in-the-Middle – CVE-2019-15006 Closed

What you need to do

Atlassian recommends that you upgrade either to the latest Enterprise release version, which is 6.13.10, or to the latest version. For a full description of the latest version of Confluence Server and Confluence Data Center, see the Release Notes. You can download the latest Confluence Server and Data Center Enterprise Release from the download center.

 

Upgrade to a fixed version of Confluence Server and Confluence Data Center.

(1) If you have a current Enterprise release  version (an Enterprise release version released on 18 December 2017 or later), or an older version (released before 2 December 2018) upgrade to the latest Enterprise release version (6.13.10):

6.13.x
6.12.x
6.11.x
6.13.10 (empfohlen)

(2) If you have a current feature version (a feature version released on 18 June 2019 or later), upgrade to the next bug-fix version of your current feature version.

7.1.x 7.1.2
7.0.x 7.0.5
6.15.x 6.15.10

(3) If you have an older version (a feature version released before 18 June 2019) but cannot upgrade to an Enterprise Release version, upgrade to any of these versions.

6.14.x 6.15.10
7.0.5
7.1.2
7.2.0

Mitigation

If you are unable to upgrade Confluence Server or Data Center immediately, or are in the process of migrating to Confluence Cloud, then as a temporary workaround, you can update the Confluence Previews plugin manually, or disable Companion App integration in the Confluence Previews plugin.

 

If you have Confluence 6.13 and later, manually upgrade the plugin

To upgrade the Confluence Previews plugin:

  1. Download the appropriate version of the Confluence Previews plugin for your version of Confluence from the table below.
  2. Go to  > Manage apps.
  3. Choose Upload and follow the prompts to manually install the plugin.

 

Confluence 7.1.x confluence-previews-9.1.5
Confluence 7.0.x confluence-previews-9.0.4
Confluence 6.15.7 – 6.15.10 confluence-previews-8.2.2
Confluence 6.15.0 – 6.15.6 confluence-previews-8.1.5
Confluence 6.14.x confluence-previews-8.0.7
Confluence 6.13.x (Enterprise release) confluence-previews-7.0.19

To confirm the plugin was updated correctly go to  > Manage apps and search for Confluence Previews plugin. Expand the listing, and check the version number matches the plugin version listed above for your version of Confluence.

 

If you have Confluence 6.11 or 6.12, disable the Companion App integration

This will disable the “Edit with” functionality. To disable the Atlassian Companion App integration:

  1. Go to  > Manage apps.
  2. Choose System Apps from the drop-down menu then search for Confluence Previews.
  3. Click to expand the list of plugin modules.
  4. Disable the following plugin modules. Not all of these modules may be present in your version of the plugin.
    • Edit With plugin for the Media Viewer (companion-plugin)
    • Embedded ‘Edit With’ button (embedded-edit)
    • ADCClient AMD Wrapper (companion-client-wrapper)
    • Edit With button (companion-plugin-button)
    • Templates for Edit With feature (companion-plugin-templates)

To confirm the Companion App integration was disabled successfully, insert a file into a page. View the page and click the file thumbnail to view the file in the preview. The “Edit with” menu should not appear.