ICS Advisory (ICSA-21-112-02)

Mitsubishi Electric GOT

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1. EXECUTIVE SUMMARY

  • CVSS v3 5.9
  • ATTENTION: Exploitable remotely
  • Vendor: Mitsubishi Electric
  • Equipment: GOT
  • Vulnerability: Improper Authentication

2. RISK EVALUATION

Successful exploitation of this vulnerability may allow an attacker to gain unauthorized access.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Mitsubishi Electric reports the vulnerability affects the VNC function of the following devices: 

  • GOT2000 series
    • GT27 model: All versions
    • GT25 model: All versions
    • GT21 model: All versions
      • GT2107-WTBD: All versions
      • GT2107-WTSD: All versions
  • GOT SIMPLE series
    • GS21 model
      • GS2110-WTBD-N: All versions
      • GS2107-WTBD-N: All versions

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER AUTHENTICATION CWE-287

A password authentication bypass vulnerability exists in the VNC function of the GOT2000 series and the GOT SIMPLE series due to improper authentication. 

CVE-2021-20590 has been assigned to this vulnerability. A CVSS v3 base score of 5.9 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N).

3.3 BACKGROUND

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

3.4 RESEARCHER

Mitsubishi Electric reported this vulnerability to CISA.

4. MITIGATIONS

Mitsubishi Electric instructs users to restrict access to the product only from trusted networks and hosts until they complete additional mitigations.

Please refer to the Mitsubishi Electric website for details.

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. This vulnerability has high attack complexity.


Contact Information

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

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

For industrial control systems cybersecurity information:  https://us-cert.cisa.gov/ics 
or incident reporting:  https://us-cert.cisa.gov/report

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