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AUSCERT External Security Bulletin Redistribution
ESB-2022.2276
Mitsubishi Electric MELSOFT GT OPC UA
11 May 2022
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AusCERT Security Bulletin Summary
---------------------------------
Product: Mitsubishi Electric MELSOFT GT OPC UA
Publisher: ICS-CERT
Operating System: Network Appliance
Resolution: Patch/Upgrade
CVE Names: CVE-2021-23840 CVE-2021-3712
Original Bulletin:
https://us-cert.cisa.gov/ics/advisories/icsa-22-130-06
Comment: CVSS (Max): 7.5 CVE-2021-23840 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVSS Source: ICS-CERT
Calculator: https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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ICS Advisory (ICSA-22-130-06)
Mitsubishi Electric MELSOFT GT OPC UA
Original release date: May 10, 2022
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 7.5
o ATTENTION: Exploitable remotely/low attack complexity
o Vendor: Mitsubishi Electric
o Equipment: MELSOFT GT OPC UA Client
o Vulnerabilities: Out-of-bounds Read, Integer Overflow or Wraparound
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow a remote attacker
to send specially crafted messages, resulting in information disclosure or a
denial-of-service condition.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following products and version combinations using OPC UA Client Connections
are affected:
o MELSOFT GT OPC UA Client: Versions 1.00A to 1.02C
o GT SoftGOT2000: Versions 1.215Z to 1.270G
3.2 VULNERABILITY OVERVIEW
3.2.1 OUT-OF-BOUNDS READ CWE-125
The affected product is vulnerable due to an out-of-bounds read, which may
allow an attacker to send specially crafted messages to disclose information on
memory or cause a denial-of-service condition.
CVE-2021-3712 has been assigned to this vulnerability. A CVSS v3 base score of
7.4 has been assigned; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:N/S:U/C:H/
I:N/A:H ).
3.2.2 INTEGER OVERFLOW OR WRAPAROUND CWE-190
The affected product is vulnerable due to an integer overflow, which may allow
an attacker to cause a denial-of-service condition.
CVE-2021-23840 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/C:N/
I:N/A:H ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Japan
3.4 RESEARCHER
Mitsubishi Electric reported these vulnerabilities to CISA.
4. MITIGATIONS
Mitsubishi Electric recommends users update software to the latest versions
below. Users will need to contact a Mitsubishi representative to obtain the
updates:
o MELSOFT GT OPC UA Client: Update to 1.03D or later
o GT SoftGOT2000: Update to 1.275M or later
Mitsubishi Electric recommends users take the following mitigations to minimize
the risk of exploiting these vulnerabilities:
o When connecting the products to the Internet, use a virtual private network
(VPN, etc.) to prevent spoofing and sniffing.
o Use the products within the LAN and block access from untrusted networks
and hosts.
o Update the OPC UA server to the latest version.
o Install antivirus software.
o Restrict physical access to computers and network equipment that use the
affected products.
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 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 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 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 these vulnerabilities.
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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