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Advisory ID: SYSS-2020-030
Product: Jira module "Gantt-Chart for Jira"
Manufacturer: Frank Polscheit - Solutions & IT-Consulting
Affected Version(s): <=5.5.4
Tested Version(s): 5.5.3, 5.5.4
Vulnerability Type: Cross-Site Scripting (CWE-79)
Risk Level: Medium
Solution Status: Fixed
Manufacturer Notification: 2020-07-23
Solution Date: 2020-07-31
Public Disclosure: 2020-08-03
CVE Reference: CVE-2020-15944
Author of Advisory: Sebastian Auwaerter, SySS GmbH

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Overview:

Gantt-Chart for Jira is a Jira module for displaying Gantt charts.

The manufacturer describes the product as follows (see [1]):

"High performance Gantt-Chart capable to display multi-projects with
10.000+ issues aggregating them as top-level big picture"

Due to missing validation of user input, the module is vulnerable to
a persistent cross-site scripting attack. As described in
security advisory SYSS-2020-029 (see [4]), it is also possible to
attack other users with this attack vector.

To exploit this vulnerability, an attacker has to be authenticated.

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Vulnerability Details:

The vulnerability exists because the names of newly created filters
are not properly sanitized by the extension. A simple attack vector
like "<script>alert('XSS')</script>" can be chosen as the name of
a filter and is then displayed on every load of the vulnerable module.

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Proof of Concept (PoC):

This security vulnerability can be reproduced by simply creating a new
filter with the "filter name" "<script>alert('XSS')</script>". Whenever
the dashboard with the vulnerable module is loaded, the attack vector
gets executed.

The following request is sent to the web server:

PUT /rest/gantt/1.0/user/properties/<chart_id>?userKey=<your_user_name>
HTTP/1.1
Host: <victim_host>
[...]

[...]"filters":{{"search":""},"<script>alert(\"XSS\")</script>"}[...]

!!! This filter can not be easily removed via the web interface. !!!
!!!                   Use with caution.                          !!!

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Solution:

Update to software version 5.5.5

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Disclosure Timeline:

2020-07-21: Vulnerability discovered
2020-07-23: Vulnerability reported to manufacturer
2020-07-31: Patch released by manufacturer
2020-08-03: Public disclosure of vulnerability

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References:

[1] Product Website for Jira Module "Gantt-Chart"

https://marketplace.atlassian.com/apps/28997/gantt-chart-for-jira?hosting=cloud&tab=overview
[2] SySS Security Advisory SYSS-2020-030

https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-030.txt
[3] SySS Responsible Disclosure Policy
    https://www.syss.de/en/news/responsible-disclosure-policy/
[4] SySS Security Advisory SYSS-2020-029

https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-029.txt

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Credits:

This security vulnerability was found by Sebastian Auwaerter of SySS
GmbH.

E-Mail: sebastian.auwaerter@syss.de
Public Key:
https://www.syss.de/fileadmin/dokumente/PGPKeys/Sebastian_Auwaerter.asc
Key Fingerprint: F98C 3E12 6713 19D9 9E2F BE3E E9A3 0D48 E2F0 A8B6

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Disclaimer:

The information provided in this security advisory is provided "as is"
and without warranty of any kind. Details of this security advisory may
be updated in order to provide as accurate information as possible. The
latest version of this security advisory is available on the SySS website.
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