Operating System:

[Appliance]

Published:

15 September 2021

Protect yourself against future threats.

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.3093
              Advisory (icsa-21-257-01) Digi PortServer TS 16
                             15 September 2021

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Digi PortServer TS 16
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Execute Arbitrary Code/Commands -- Remote/Unauthenticated
                   Reduced Security                -- Remote/Unauthenticated
Resolution:        Alternate Program
CVE Names:         CVE-2021-38412  

Original Bulletin: 
   https://us-cert.cisa.gov/ics/advisories/icsa-21-257-01

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ICS Advisory (ICSA-21-257-01)

Digi PortServer TS 16

Original release date: September 14, 2021

Legal Notice

All information products included in https://us-cert.cisa.gov/ics are provided
"as is" for informational purposes only. The Department of Homeland Security
(DHS) does not provide any warranties of any kind regarding any information
contained within. DHS does not endorse any commercial product or service,
referenced in this product or otherwise. Further dissemination of this product
is governed by the Traffic Light Protocol (TLP) marking in the header. For more
information about TLP, see https://us-cert.cisa.gov/tlp/ .



1. EXECUTIVE SUMMARY

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

  o Firmware Version 82000684
  o 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

  o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Communications,
    Information Technology, Transportation Systems
  o COUNTRIES/AREAS DEPLOYED: Worldwide
  o 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:

  o Minimize network exposure for all control system devices and/or systems,
    and ensure that they are not accessible from the Internet .
  o Locate control system networks and remote devices behind firewalls, and
    isolate them from the business network.
  o 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.

For any questions related to this report, please contact the CISA at:

Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870

CISA continuously strives to improve its products and services. You can help by
choosing one of the links below to provide feedback about this product.

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