Johnson Controls Facility Explorer

1. EXECUTIVE SUMMARY

• CVSS v3 8.8
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Johnson Controls
• Equipment: Facility Explorer
• Vulnerability: Improper Privilege Management

2. RISK EVALUATION

Successful exploitation of this vulnerability could give an authenticated user an unintended level of access to the controller’s file system.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Johnson Controls reports this vulnerability affects the following product:

• Facility Explorer SNC Series Supervisory Controller: Version 11

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER PRIVILEGE MANAGEMENT CWE-269

Sending specifically crafted web messages to the Facility Explorer SNC Series Supervisory Controller (F4-SNC) could give an authenticated F4-SNC user unintended access to the controller’s file system, which may allow an attacker to access or modify system files.

CVE-2021-27661 has been assigned to this vulnerability. A CVSS v3 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Ireland

3.4 RESEARCHER

Johnson Controls, Inc. reported this vulnerability to CISA.

4. MITIGATIONS

Johnson Controls recommends users apply a patch to the Facility Explorer SNC Series Supervisory Controllers (F4-SNC).

For more detailed mitigation instructions, please see Johnson Controls Product Security Advisory JCI-PSA-2021-11 v1

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
• When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as its connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.



CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.cisa.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.



Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.

No known public exploits specifically target this vulnerability.