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AUSCERT External Security Bulletin Redistribution
Advisory (icsa-21-112-02) Mitsubishi Electric GOT
23 April 2021
AusCERT Security Bulletin Summary
Product: Mitsubishi Electric GOT SIMPLE series products
Mitsubishi Electric GOT2000 series products
Operating System: Network Appliance
Impact/Access: Unauthorised Access -- Remote/Unauthenticated
CVE Names: CVE-2021-20590
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ICS Advisory (ICSA-21-112-02)
Mitsubishi Electric GOT
Original release date: April 22, 2021
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1. EXECUTIVE SUMMARY
o CVSS v3 5.9
o ATTENTION: Exploitable remotely
o Vendor: Mitsubishi Electric
o Equipment: GOT
o Vulnerability: Improper Authentication
2. RISK EVALUATION
Successful exploitation of this vulnerability may allow an attacker to gain
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Mitsubishi Electric reports the vulnerability affects the VNC function of the
o GOT2000 series
GT27 model: All versions
GT25 model: All versions
GT21 model: All versions
GT2107-WTBD: All versions
GT2107-WTSD: All versions
o GOT SIMPLE series
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/
o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Japan
Mitsubishi Electric reported this vulnerability to CISA.
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:
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
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.
For any questions related to this report, please contact the CISA at:
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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