Atlassian Confluence 6.1.1 Access Restriction Bypass

`SEC Consult Vulnerability Lab Security Advisory < 20170613-0 >  
=======================================================================  
title: Access Restriction Bypass  
product: Atlassian Confluence  
vulnerable version: 4.3.0 - 6.1.1  
fixed version: 6.2.1  
CVE number: -  
impact: Medium  
homepage: https://www.atlassian.com/  
found: 2017-03-27  
by: Mathias Frank (Office Vienna)  
SEC Consult Vulnerability Lab  
  
An integrated part of SEC Consult  
Bangkok - Berlin - Linz - Luxembourg - Montreal - Moscow  
Kuala Lumpur - Singapore - Vienna (HQ) - Vilnius - Zurich  
  
https://www.sec-consult.com  
  
=======================================================================  
  
Vendor description:  
-------------------  
"In 2002, our founders, Scott Farquhar and Mike Cannon-Brookes, set  
conventional wisdom on its ear by launching a successful enterprise  
software company with no sales force. From Australia. Our first product, JIRA,  
proved that if you make a great piece of software, price it right, and make  
it available to anyone to download from the internet, teams will come. And  
they'll build great things with it. And they'll tell two friends, and so on,  
and so on.  
Today a lot has changed. We're over 1,700 Atlassians (and growing), in six  
locations, with products to help all types of teams realize their visions and  
get stuff done. But the fundamentals remain the same. We're for teams because  
we believe that great teams can do amazing things. We're not afraid to do  
things differently. And we're driven by an inspiring set of values that shape  
our culture and our products for the better."  
  
Source: https://www.atlassian.com/company  
  
  
Business recommendation:  
------------------------  
SEC Consult recommends to upgrade to the latest version available which fixes  
the identified issue.  
  
  
Vulnerability overview/description:  
-----------------------------------  
1) Access Restriction Bypass  
The "watch" functionality provides a user the option to subscribe to specific  
content. Furthermore, the user gets a notification for any new comment made to the  
previously subscribed content.  
  
A user can manually subscribe to pages which he is not able to view and he then  
receives any further comment made on the restricted page.  
  
  
Proof of concept:  
-----------------  
1) Access Restriction Bypass  
Prerequisite as admin user just for a proof of concept demo page:  
* Create a Space "Demo Space" visible for every user and group  
* Create a Page "Demo Page" (example pageID: 1048582) and restrict the  
"Viewing and editing restriction" to only the administrator group/user with  
the "/pages/getcontentpermissions.action" function.  
  
  
Send the following request as user:  
------------------------------------------------------------------------------  
POST /users/addpagenotificationajax.action HTTP/1.1  
Host: localhost:8090  
Referer: http://localhost:8090/display/ds/Welcome+to+Confluence  
Content-Type: application/x-www-form-urlencoded; charset=UTF-8  
X-Requested-With: XMLHttpRequest  
[...]  
  
pageId=1048582&atl_token=1b5ee6615c44e4067679ccfa6e5904f0e42e8eb7  
------------------------------------------------------------------------------  
  
Then the user is subscribed to the "Demo Page" and receives a notification and is  
able to receive any further comments made on the subscribed page.  
  
  
Vulnerable / tested versions:  
-----------------------------  
The following version has been tested by SEC Consult  
Atlassian Confluence version 5.9.14 and 6.1.1  
  
Atlassian believes that versions beginning from 4.3.0 before 6.2.1 are affected.  
  
  
Vendor contact timeline:  
------------------------  
2017-04-03: Contacting vendor through [email protected]  
2017-04-05: Vendor confirmed the vulnerability and issued the references  
CONFSERVER-52241 (Confluence Server) and CONFCLOUD-54634 (Confluence  
Cloud)  
2017-04-13: Vendor fixed the issue CONFCLOUD-54634.  
2017-05-11: Asked for planned timeline and release of an fix for CONFSERVER-52241.  
2017-05-29: Vendor released a fix for CONFSERVER-52241 with version 6.2.1.  
2017-06-08: Vendor prepares a sanitised copy of CONFSERVER-52241 for release along  
with the advisory - https://jira.atlassian.com/browse/CONFSERVER-52560  
2017-06-13: Public release of advisory.  
  
  
Solution:  
---------  
Upgrade to version 6.2.1 available at:  
https://www.atlassian.com/software/confluence/download  
The effectiveness of the fix was verified by the SEC Consult Vulnerability Lab.  
  
https://jira.atlassian.com/browse/CONFSERVER-52560  
  
  
Workaround:  
-----------  
Disable workbox notifications as per the instructions found at  
https://confluence.atlassian.com/doc/configuring-workbox-notifications-301663830.html  
  
  
Advisory URL:  
-------------  
https://www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm  
  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
SEC Consult Vulnerability Lab  
  
SEC Consult  
Bangkok - Berlin - Linz - Luxembourg - Montreal - Moscow  
Kuala Lumpur - Singapore - Vienna (HQ) - Vilnius - Zurich  
  
About SEC Consult Vulnerability Lab  
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult. It  
ensures the continued knowledge gain of SEC Consult in the field of network  
and application security to stay ahead of the attacker. The SEC Consult  
Vulnerability Lab supports high-quality penetration testing and the evaluation  
of new offensive and defensive technologies for our customers. Hence our  
customers obtain the most current information about vulnerabilities and valid  
recommendation about the risk profile of new technologies.  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
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EOF Mathias Frank / @2017  
  
`