Journyx Reflected Cross Site Scripting

Vulnerability Details

Affected Vendor: Journyx
Affected Product: Journyx (jtime)
Affected Version: 11.5.4
Platform: GNU/Linux
CWE Classification: CWE-81: Improper Neutralization of Script in an Error
Message Web Page
CVE ID: CVE-2024-6892

Vulnerability Description

Attackers can craft a malicious link that once clicked
will execute arbitrary JavaScript in the context of
the Journyx web application.

Technical Description

During the active directory login flow, if an error
occurs, the user is redirected to a page containing
an error message outlining the problem. The error
message shown in the page response is derived from
the “error_description” query parameter that appears
in the URL. This parameter is not sanitized or validated
prior to being reflected, allowing for an attacker to
insert malicious HTML/JavaScript into the “error_description”
parameter.

This vulnerability can be exploited regardless of whether
active directory authentication has been configured for the
Journyx instance.

Mitigation and Remediation Recommendation

The vendor reports that this issue was remediated in Journyx
v13.0.0.

For self-hosted instances of JournyX, additional security
measures (such as input sanitization) can be added by monkey
patching the PYC file responsible for handling request
parameters (mycgi.pyc).

1. Rename “mycgi.pyc” to an alternative name, e.g. mycgi_original.pyc.
   $ mv wt_tar/pi/pylib/wtlib/mycgi.py wt_tar/pi/pylib/wtlib/mycgi_original.py

2. Create a file named “mycgi.py” in the same directory.
   $ touch wt_tar/pi/pylib/wtlib/mycgi.py

3. Insert the following code into the newly created “mycgi.py”

   from mycgi_original import *
   from html import escape

   def patch():
   pdata = _parse()

     # force the value of "end_URL" to always be "wte"
     if pdata.get('end_URL'): pdata['end_URL'] = ['wte']
   
     # sanitize user-controlled error messages
     for parameter in ['error', 'error_description']:
         if not pdata.get(parameter): continue
         pdata[parameter] = [escape(value) for value in pdata[parameter]]
   
     return pdata
   

   _parse = parse
   parse = patch

Once these changes have been made, the JournyX native “mycgi.parse()”
function will be overwritten with the “patch()” function located in the
“mycgi.py” file. Relevant to this advisory, the patch provided above
will replace special characters with their respective HTML entity
representation for the “error” and “error_description” parameters. This
list of parameters can be extended as needed.

Additionally, if SSO is not required, requests to /jtcgi/r/adlogin/sso
could be dropped without forwarding invoking FastCGI via a ModSecurity
rule like the one below:

   SecRule REQUEST_URI "@contains adlogin/sso" "id:4,phase:2,deny,log,auditlog"

Credit

This vulnerability was discovered by Jaggar Henry of KoreLogic, Inc.

Disclosure Timeline

2024.01.31 - KoreLogic notifies Journyx support of the intention to
report vulnerabilities discovered in the licensed,
on-premises version of the product.
2024.01.31 - Journyx acknowledges receipt.
2024.02.02 - KoreLogic requests a meeting with Journyx support to share
vulnerability details.
2024.02.07 - KoreLogic reports vulnerability details to Journyx.
2024.02.09 - Journyx responds that this vulnerability has been remediated
in the cloud-hosted version of the product.
2024.02.21 - KoreLogic offers to test the cloud version to confirm
the fix; no response.
2024.07.01 - KoreLogic notifies Journyx of impending public disclosure.
2024.07.09 - Journyx confirms version number of the remediation.
2024.08.07 - KoreLogic public disclosure.

Proof of Concept

The following URL contains the “error_description”
parameter with a value of “%3Csvg%2fonload%3dprompt(%27KoreLogic%27)%3E”:

 http://redacted.com:8080/jtcgi/r/adlogin/sso?code=1337&state=foobar&id_token=zoinks&error_description=%3Csvg%2fonload%3dprompt(%27KoreLogic%27)%3E&error=error

This value is automatically URL decoded to “<svg/onload=prompt(‘KoreLogic’)>”
and reflected into the page response:

 <div>
     Unable to complete sign-on attempt. This is possibly a configuration error in the application registration on the Identity Provider (IdP) side. The IdP server said: 
     <p>error <b>&lt;svg onload="prompt('KoreLogic')"&gt;&lt;/svg&gt;</b></p>
 </div>

Once this link is clicked or visited in a browser, the
javascript function “prompt()” is executed, and a display
box is presented, thereby validating the execution of
arbitrary JavaScript.