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Advisory ID:               SYSS-2020-037
Product:                   MailDepot
Manufacturer:              REDDOXX GmbH
Affected Version(s):       2033 (2.3.3022)
Tested Version(s):         2033 (2.3.3022)
Vulnerability Type:        Persistent Cross-site Scripting (CWE-79)
Risk Level:                High
Solution Status:           Open
Manufacturer Notification: 2020-10-01
Solution Date:             2020-11-11
Public Disclosure:         2020-11-13
CVE Reference:             CVE-2020-26554
Authors of Advisory:       Micha Borrmann, Thomas Engel (SySS GmbH)

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Overview:

REDDOXX MailDepot is  an e-mail archiving solution  with many features
and an optional web browser user interface.

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

"The email  archiving solution  works independently  from the  type of
mail server, supports any type of  storage and can therefore be easily
integrated into any existing infrastructure."

Due to the improper  server-side invalidation of authentication tokens
when using  the logout  function, authentication  tokens can  still be
used.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Vulnerability Details:

The web-based application displays the entire content of HTML e-mails.
Also, external  resources like images  or JavaScript will  be executed
during the display of an e-mail. In addition, the subject field is not
sanitized and  allows the injection  of JavaScript code which  will be
executed when an e-mail is displayed.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Proof of Concept (PoC):

There are a lot of tools that generate HTML mails including JavaScript.

The following part in an HTML e-mail illustrates the security issue:

<img src="https://www.example.org/xss.png">
<script>alert("XSS Demonstration")</script>
<script src="https://www.example.org/xss.js"></script>

The subject of an e-mail may  contain the following code which will be
executed when the e-mail is viewed:

<img src=X onerror='alert("XSS Demonstration")'</script>

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Solution:

Install the provided hotfix 43-restproxy-usergui [2]

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Disclosure Timeline:

2020-09-30: Detection of the vulnerability
2020-10-01: Vulnerability reported to manufacturer
2020-10-04: CVE number assigned
2020-10-05: Manufacturer confirms vulnerability
2020-11-11: Hotfix was released by the vendor
2020-11-13: Public release of the security advisory

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References:

[1] REDDOXX MailDepot Product Website
    https://www.reddoxx.com/en/products/archiving/
[2] REDDOXX Release Notes
    https://appliance.docs.reddoxx.com/de/release-notes/release-notes-version-2033-final-2-3-3022
[3] SySS Security Advisory SYSS-2020-037
    https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-037.txt
[4] SySS Responsible Disclosure Policy
    https://www.syss.de/en/responsible-disclosure-policy/

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Credits:

This security vulnerability was found by Micha Borrmann and Thomas
Engel of SySS GmbH.

E-Mail: micha.borrmann (at) syss.de
Public Key: https://www.syss.de/fileadmin/dokumente/PGPKeys/Micha_Borrmann.asc
Key Fingerprint: 38BD 7A9C 3EA9 39C5 33F9  94D0 CFC2 D5B0 8EE0 CBB9

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Copyright:

Creative Commons - Attribution (by) - Version 3.0
URL: http://creativecommons.org/licenses/by/3.0/deed.en
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