ICS Advisory (ICSA-20-324-05)

Mitsubishi Electric MELSEC iQ-R Series

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1. EXECUTIVE SUMMARY

  • CVSS v3 7.5
  • ATTENTION: Exploitable remotely/low skill to exploit
  • Vendor: Mitsubishi Electric
  • Equipment: MELSEC iQ-R series
  • Vulnerability: Uncontrolled Resource Consumption

2. RISK EVALUATION

Successful exploitation of this vulnerability could cause a denial-of-service condition for the affected product.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Mitsubishi Electric reports the vulnerability affects the following MELSEC iQ-R series CPU module products: 

  • R00/01/02CPU firmware Versions 19 and earlier
  • R04/08/16/32/120(EN)CPU firmware Versions 51 and earlier
  • R08/16/32/120SFCPU firmware Versions 22 and earlier
  • R08/16/32/120PCPU all versions
  • R08/16/32/120PSFCPU all versions
  • RJ71EN71 firmware Versions 47 and earlier
  • RJ71GF11-T2 firmware Versions 47 and earlier
  • RJ72GF15-T2 firmware Versions 07 and earlier
  • RJ71GP21-SX firmware Versions 47 and earlier
  • RJ71GP21S-SX firmware Versions 47 and earlier
  • RJ71C24(-R2/R4) all versions
  • RJ71GN11-T2 all versions 

3.2 VULNERABILITY OVERVIEW

3.2.1    UNCONTROLLED RESOURCE CONSUMPTION CWE-400

A vulnerability in MELSEC iQ-R series modules causes uncontrolled resource consumption. When a module receives a specially crafted SLMP packet from a malicious attacker, the program execution and communication could enter a denial-of-service condition.

CVE-2020-5668 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

Xiaofei.Zhang reported this vulnerability to Mitsubishi Electric.

4. MITIGATIONS

Mitsubishi Electric has issued the following iQ-R Series firmware versions to address this issue:

  • R00/01/02CPU: firmware Versions 20 or later
  • R04/08/16/32/120 (EN) CPU: firmware Versions 52 or later
  • R08/16/32/120SFCPU: firmware Versions 23 or later
  • RJ71EN71: firmware Versions 48 or later
  • RJ71GF11-T2: firmware Versions 48 or later
  • RJ72GF15-T2: firmware Versions 08 or later
  • RJ71GP21-SX: firmware Versions 48 or later
  • RJ71GP21S-SX: firmware Versions 48 or later

Mitsubishi Electric also recommends the following practices 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.

For more information about this vulnerability and the associated mitigations, please see the vulnerability information on the Mitsubishi website.

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.


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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