1. EXECUTIVE SUMMARY

  • CVSS v3 5.3
  • ATTENTION: Exploitable remotely/Low attack complexity
  • Vendor: Mitsubishi Electric
  • Equipment: MELSEC iQ-R Series
  • Vulnerability: Resource Exhaustion

2. UPDATE INFORMATION

This updated advisory is a follow-up to the advisory update titled ICSA-20-161-02 Mitsubishi Electric MELSEC iQ-R series (Update B) that was published November 5, 2020 to the ICS webpage on us-cert.cisa.gov.

3. RISK EVALUATION

Successful exploitation of this vulnerability could cause the Ethernet port to enter a denial-of-service condition.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

Mitsubishi Electric reports that the vulnerability affects the following MELSEC iQ-R series modules: 

  • R00/01/02CPU: Firmware Versions 7 or earlier
  • R04/08/16/32/120CPU, R04/08/16/32/120ENCPU: Firmware Versions 39 or earlier
  • R08/16/32/120SFCPU: Firmware Versions 20 or earlier
  • R08/16/32/120PCPU: Firmware Versions 24 or earlier
  • R08/16/32/120PSFCPU: Firmware Versions 05 or earlier
  • RJ71EN71: Firmware Versions 49 or earlier

4.2 VULNERABILITY OVERVIEW

4.2.1    UNCONTROLLED RESOURCE CONSUMPTION (‘RESOURCE EXHAUSTION’) CWE-400

——— Begin Update C Part 1 of 1 ———

An attacker can cause a denial-of-service condition at the Ethernet port by sending a specially crafted packet.

——— End Update C Part 1 of 1 ———

CVE-2020-13238 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

4.3 BACKGROUND

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

4.4 RESEARCHER

Yossi Reuven of SCADAfence reported this vulnerability to Mitsubishi Electric.

5. MITIGATIONS

Mitsubishi Electric has fixed the following versions to discard packets when specially crafted packets are received:

  • R00/01/02CPU: Firmware Versions 8 or later
  • R04/08/16/32/120CPU, R04/08/16/32/120ENCPU: Firmware Versions 40 or later
  • R08/16/32/120SFCPU: Firmware Versions 21 or later
  • R08/16/32/120PCPU: Firmware Versions 25 or later
  • R08/16/32/120PSFCPU: Firmware Versions 06 or later
  • RJ71EN71: Firmware Versions 50 or later

Mitsubishi Electric recommends users of the affected devices take the following measures for cyber-attacks such as DoS attack or unauthorized access from untrusted networks or hosts.

  • Connection to untrusted networks or hosts: Check whether the modules mounted in the equipment used are connected to untrusted networks or hosts.
  • Firewalls: If the modules are connected to untrusted networks or hosts, check whether measures such as firewalls are properly configured.

Please see the publication from Mitsubishi Electric for more information.

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

  • Use secure methods when remote access is required, such as virtual private networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the 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 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.

Source:

https://us-cert.cisa.gov/ics/advisories/icsa-20-161-02