Johnson Controls Metasys 

1. EXECUTIVE SUMMARY

• CVSS v3 6.8
• ATTENTION: Exploitable remotely
• Vendor: Johnson Controls
• Equipment: Metasys
• Vulnerabilities: Reusing a Nonce, Key Pair in Encryption; Use of Hard-coded Cryptographic Key

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could be leveraged by an attacker to decrypt captured network traffic.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Metasys building automation system are affected:

• Metasys system versions prior to 9.0

3.2 VULNERABILITY OVERVIEW

3.2.1    REUSING A NONCE, KEY PAIR IN ENCRYPTION CWE-323

Metasys ADS/ADX servers and NAE/NIE/NCE engines make use of a shared RSA key pair for certain encryption operations involving the Site Management Portal (SMP). An attacker with access to the shared RSA key pair could decrypt captured network traffic between the Metasys ADS/ADX servers or NAE/NIE/NCE engines and the connecting SMP user client.

CVE-2019-7593 has been assigned to this vulnerability. A CVSS v3 base score of 6.8 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N).

3.2.2    USE OF HARD-CODED CRYPTOGRAPHIC KEY CWE-321

Metasys ADS/ADX servers and NAE/NIE/NCE engines make use of a hardcoded RC2 key for certain encryption operations involving the Site Management Portal (SMP). An attacker with access to the hardcoded RC2 key could decrypt captured network traffic between the Metasys ADS/ADX servers or NAE/NIE/NCE engines and the connecting SMP user client.

CVE-2019-7594 has been assigned to this vulnerability. A CVSS v3 base score of 6.8 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N).

3.3 BACKGROUND

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

3.4 RESEARCHER

harpocrates.ghost@protonmail.com reported these vulnerabilities to Johnson Controls.

4. MITIGATIONS

Johnson Controls recommends the following:

• Users should upgrade to Version 9.0 or later and configure sites with trusted certificates.
• Further ICS security notices and product security guidance are located at the Johnson Controls product security website.

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 that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the 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.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.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 these vulnerabilities. High skill level is needed to exploit.