Subnet Solutions Inc. PowerSYSTEM Center

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1. EXECUTIVE SUMMARY

• CVSS v3 7.8
• ATTENTION: Low attack complexity
• Vendor: Subnet Solutions Inc.
• Equipment: PowerSYSTEM Center
• Vulnerability: Unquoted Search Path or Element

2. RISK EVALUATION

Successful exploitation of this vulnerability could result in an attacker achieving arbitrary code execution and privilege escalation through the unquoted service path.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of PowerSYSTEM Center, a multi-function management platform, are affected:

• PowerSYSTEM Center: 2020 v5.0.x through 5.16.x

3.2 Vulnerability Overview

3.2.1 UNQUOTED SEARCH PATH OR ELEMENT CWE-428

Subnet Solutions PowerSYSTEM Center versions 2020 v5.0.x through 5.16.x contain a vulnerability that could allow an authorized local user to insert arbitrary code into the unquoted service path and escalate privileges.

CVE-2023-6631 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Multiple
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Canada

3.4 RESEARCHER

Kelly Stich of Subnet Solutions Inc. reported this vulnerability to CISA.

4. MITIGATIONS

Subnet Solutions recommends users upgrade to PowerSYSTEM Center versions 2020 Update 17 or later. To obtain this software, contact Subnet Solution’s Customer Service.

Additionally, Subnet Solutions recommends users apply Application Allowlisting on PowerSYSTEM Center Device Communication Server (DCS) hosts to ensure only trusted executables are able to be run.

If unable to apply PowerSYSTEM Center 2020 Update 17, Subnet Solutions recommends users mitigate risk by logging in to the DCS as administrator, opening the Registry Editor, navigating to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services, locating all pscagent.* entries, and modifying the ImagePath key by enclosing it within double quotes ("). Restart computer when complete.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:

• Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
• Locate control system networks and remote devices behind firewalls and isolating them from business networks.
• When remote access is required, use more 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 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 cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

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

No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability is not exploitable remotely.

5. UPDATE HISTORY

• December 19, 2023: Initial Publication