ICS Advisory

Mitsubishi Electric MELSEC iQ-R Series (Update A)

Last Revised
Alert Code
ICSA-21-287-03

1. EXECUTIVE SUMMARY

  • CVSS v3 9.1
  • ATTENTION: Exploitable remotely/low attack complexity
  • Vendor: Mitsubishi Electric Corporation
  • Equipment: MELSEC iQ-R Series CPU Module
  • Vulnerability: Cleartext Transmission of Sensitive Information

2. UPDATE INFORMATION

This updated advisory is a follow-up to the original advisory titled “ICSA-21-287-03 Mitsubishi Electric MELSEC iQ-R Series” that was published October 14, 2021, on the ICS webpage on cisa.gov/ICS

3.RISK EVALUATION

Successful exploitation of this vulnerability could allow a remote attacker to be able to log in to the CPU module by obtaining credentials.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

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Mitsubishi Electric reports the vulnerability affects the following MELSEC CPU Modules: 

  • MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU: Firmware versions "26" and prior
  • MELSEC iQ-R series SIL2 Process CPU R08/16/32/120PSFCPU: all versions

4.2 VULNERABILITY OVERVIEW

4.2.1    CLEARTEXT TRANSMISSION OF SENSITIVE INFORMATION VULNERABILITY CWE-319

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An unauthorized remote attacker may be able to log in to the CPU module by obtaining credentials other than password.

CVE-2021-20599 has been assigned to this vulnerability. A CVSS v3 base score of 9.1 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

4.3 BACKGROUND

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

4.4 RESEARCHER

Ivan Speziale of Nozomi Networks reported this vulnerability to CISA.

5. MITIGATIONS

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Mitsubishi Electric has prepared the following countermeasures: 

  • MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU: Firmware versions "27" or later

Mitsubishi Electric will release updates for other products.

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Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

  • Use a firewall or virtual private network (VPN) to prevent unauthorized access when Internet access is required.
  • Use within a LAN and block access from untrusted networks and hosts through firewalls.
  • Use the IP filter function to restrict the accessible IP addresses.

Please refer to the Mitsubishi Electric advisory for further details.

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 product is provided subject to this Notification and this Privacy & Use policy.

Vendor

Mitsubishi Electric