ICS Advisory (ICSA-20-303-01)

Mitsubishi Electric MELSEC iQ-R, Q and L Series

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1. EXECUTIVE SUMMARY

  • CVSS v3 7.5
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: Mitsubishi Electric
  • Equipment: MELSEC iQ-R, Q and L Series
  • Vulnerability: Uncontrolled Resource Consumption

2. RISK EVALUATION

Successful exploitation of this vulnerability could cause a denial-of-service condition in the Ethernet port on the CPU module. 

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of MELSEC iQ-R Series are affected:

  • R 00/01/02 CPU, firmware Versions 20 and earlier
  • R 04/08/16/32/120 (EN) CPU, firmware Versions 52 and earlier
  • R 08/16/32/120 SFCPU, firmware Versions 22 and earlier
  • R 08/16/32/120 PCPU, all versions
  • R 08/16/32/120 PSFCPU, all versions
  • R 16/32/64 MTCPU, all versions

The following versions of MELSEC Q Series are affected:

  • Q03 UDECPU, Q 04/06/10/13/20/26/50/100 UDEHCPU, serial number 22081 and earlier
  • Q 03/04/06/13/26 UDVCPU, serial number 22031 and earlier
  • Q 04/06/13/26 UDPVCPU, serial number 22031 and earlier
  • Q 172/173 DCPU-S1, all versions
  • Q 172/173 DSCPU, all versions
  • Q 170 MCPU, all versions
  • Q 170 MSCPU (-S1), all versions
  • MR-MQ100, all versions

The following versions of MELSEC L Series are affected:

  • L 02/06/26 CPU (-P), L 26 CPU - (P) BT, all versions

3.2 VULNERABILITY OVERVIEW

3.2.1    UNCONTROLLED RESOURCE CONSUMPTION CWE-400

The affected product is vulnerable to uncontrolled resource consumption in the MELSEC iQ-R, Q, and L Series CPU modules. When the CPU module receives a specially crafted packet from a malicious attacker, Ethernet communication may enter a denial-of-service condition and a reset is required to recover it. 

CVE-2020-5652 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

  • 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 recommends users take the following mitigation measures to minimize the risk of exploiting this vulnerability:

  • Use a firewall or virtual private network (VPN), etc. to prevent unauthorized access when Internet access is required.
  • Use within a LAN and block access from untrusted networks and hosts through firewalls.

Please refer to Mitsubishi Electric’s website for details on available patches. Mitsubishi recommends users update their products by downloading and applying the latest versions. Please contact a Mitsubishi Electric representative for additional details.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

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.


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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