Digi PortServer TS 16

1. EXECUTIVE SUMMARY

• CVSS v3 9.6
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Digi International, Inc.
• Equipment: PortServer TS 16
• Vulnerability: Improper Authentication

2. RISK EVALUATION

Successful exploitation of this vulnerability allows write access, which grants control of settings, command execution, and access to the command line interface.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following firmware versions of Digi PortServer TS 16 are affected:

• Firmware Version 82000684
• Firmware Version 82000685

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER AUTHENTICATION CWE-287

Properly formatted POST requests to multiple resources on the HTTP and HTTPS web servers of the Digi PortServer TS 16 Rack device do not require authentication or authentication tokens. This vulnerability could allow an attacker to enable the SNMP service and manipulate the community strings to achieve further control.

CVE-2021-38412 has been assigned to this vulnerability. A CVSS v3 base score of 9.6 has been calculated; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Communications, Information Technology, Transportation Systems
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: United States

3.4 RESEARCHER

Byron Chaney of RevSec and Jason Holcomb of Accenture reported this vulnerability to CISA.

4. MITIGATIONS

The PortServer TS 16 product was discontinued in 2016. Per Digi’s security support, the device software and hardware support of 5 years has passed. Digi recommends upgrading to a new supported product. If this is not possible, extended support may be available by contacting Digi directly.

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.

• Digi