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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.3305
 Advisory (icsa-21-278-01) Mitsubishi Electric GOT and Tension Controller
                              6 October 2021

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

Product:           Mitsubishi Electric GOT and Tension Controller
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Mitigation
CVE Names:         CVE-2021-20605 CVE-2021-20604 CVE-2021-20603
                   CVE-2021-20602  

Original Bulletin: 
   https://us-cert.cisa.gov/ics/advisories/icsa-21-278-01

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ICS Advisory (ICSA-21-278-01)

Mitsubishi Electric GOT and Tension Controller

Original release date: October 05, 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
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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
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1. EXECUTIVE SUMMARY

  o CVSS v3 7.5
  o ATTENTION: Exploitable remotely/low attack complexity
  o Vendor: Mitsubishi Electric
  o Equipment: GOT and Tension Controller
  o Vulnerabilities: Improper Handling of Exceptional Conditions, Improper
    Input Validation

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to
cause a denial-of-service condition by sending specially crafted packets.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following Mitsubishi Electric products are affected:

  o GOT2000 Series GT21 Model
       GT2107-WTBD: All versions
       GT2107-WTSD: All versions
       GT2104-RTBD: All versions
       GT2104-PMBD: All versions
       GT2103-PMBD: All versions
  o GOT SIMPLE Series GS21 Model
       GS2110-WTBD: All versions
       GS2107-WTBD: All versions
       GS2110-WTBD-N: All versions
       GS2107-WTBD-N: All versions
  o Tension Controller
       LE7-40GU-L: All versions

3.2 VULNERABILITY OVERVIEW

3.2.1 IMPROPER HANDLING OF EXCEPTIONAL CONDITIONS CWE-755

An attacker could send specially crafted packets cause to cause several
different denial-of-service conditions due to the improper handling of
exceptional conditions.

CVE-2021-20602 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:N/I:N/A:H ).

3.2.2 IMPROPER INPUT VALIDATION CWE-20

An attacker could send specially crafted packets cause to cause several
different denial-of-service conditions in the TCP-IP protocol stack of GOT and
Tension Controller.

CVE-2021-20603 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:N/I:N/A:H ).

3.2.3 IMPROPER INPUT VALIDATION CWE-20

An attacker could send specially crafted packets cause to cause several
different denial-of-service conditions in the TCP-IP protocol stack of GOT and
Tension Controller.

CVE-2021-20604 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:N/I:N/A:H ).

3.2.4 IMPROPER INPUT VALIDATION CWE-20

An attacker could send specially crafted packets cause to cause several
different denial-of-service conditions in the TCP-IP protocol stack of GOT and
Tension Controller.

CVE-2021-20605 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been calculated; 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 plans to release updated, fixed versions of these products
in the future.

Mitsubishi Electric recommends users take the following mitigation measures to
minimize the risk of exploiting these vulnerabilities:

  o Use a firewall or virtual private network (VPN), etc. to prevent
    unauthorized access when Internet access is required.
  o Use within a LAN and block access from untrusted networks and host through
    firewalls.
  o Use the IP filter function to restrict the accessible IP addresses. Please
    see the following manuals about IP filter function:
       GT Designer3 (GOT2000) Screen Design Manual (SH-081220ENG) "5.4.3
        Setting the IP filter"
       GOT support for the IP filter function (Tension Controller does not
        support it)

For additional questions, please refer to the Mitsubishi Electric support
website .

For specific update instructions and additional details see the Mitsubishi
Electric advisory .

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 .

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 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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